They estimated the thoroughness and accuracy of his work much higher than later ages have done. But this respect, which enhanced the magnitude of his work in their eyes, at the same time inspired many of them with a desire to imitate him.
Thus a school of church historians arose, and a number of continuations of Eusebius' History were undertaken. Of these, six are known to have seen the light: three of these again are either in part or wholly lost; viz., those of Philippus Sidetes, of Philastorgius, and of Hesychius. The first because of internal characteristics which made it difficult to use; the second because its author was a heretic (an Arian), and with the wane of the sect to which he belonged, his work lost favor and was gradually ostracized by the orthodox, and thus was lost, with the exception of an abstract preserved by Photius; and the third, for reasons unknown and undiscoverable, met with the same fate, not leaving even as much as an abstract behind. The remaining three are the histories of Socrates, Sozomen, and Theodoret. That of Theodoret begins with the rise of Arianism, and ends with Theodore of Mopsuestia (429 a.d.). That of Sozomen was begun with the purpose of including the history of the years between 323 (date of the overthrow of Licinius by Constantine) and 439 (the seventeenth consulship of Theodosius the Younger), but for some reason was closed with the death of the Emperor Honorius (423), and so covers just one hundred years. The work of Socrates, being evidently older than either of the other two, is more directly a continuation of the Ecclesiastical History of Eusebius. The motives which actuated him to continue the narratives of Eusebius may be gathered from the work to be his love for history,  especially that of his own times,  his respect for Eusebius, and the exhortation of Theodorus, to whom the work is dedicated.  The author opens with a statement of his purpose to take up the account where Eusebius had left it off, and to review such matters as, according to his judgment, had not been adequately treated by his predecessor. Accordingly he begins with the accession of Constantine (306 a.d.), when the persecution begun by Diocletian came to an end, and stops with the year 439. He mentions the number of years included in his work as 140. As a matter of fact, only 133 years are recorded; but the number given by the author is doubtless not meant to be rather a round than a precise number. The close of his history is the seventeenth consulship of Theodosius the Younger -- the same as the proposed end of Sozomen's work. Why Socrates did not continue his history later is not known, except perhaps because, as he alleges, peace and prosperity seemed to be assured to the church, and history is made not in time of peace, but in the turmoils and disturbances of war and debate. The period covered by the work is very eventful. It is during this period that three of the most important councils of the church were held: those of Nicæa (325), of Constantinople (381), and the first council of Ephesus (431), besides the second of Ephesus, called the "Robbers' Council" (lestrike), and that of Chalcedon, which were held not much later. It is this period which saw the church coming to the ascendant. Instead of its being persecuted, or even merely tolerated, it then becomes dominant. With its day of peace from without comes the day of its internal strife, and so various sects and heresies spring up and claim attention in church history. Socrates appreciated the importance which these contentions gave to his work. 
Geographically Socrates' work is limited to the East. The western branch of the church is mentioned in it only as it enters into relations with the eastern. The division of the history into seven books is made on the basis of the succession in the eastern branch of the Roman Empire. The seven books cover the reigns of eight eastern emperors. Two of these reigns -- that of Julian (361-363) and that of Jovian (363-364) -- were so brief that they are combined and put into one book, but otherwise the books are each devoted to the reign of one emperor. The first book treats of the church under Constantine the Great (306-337); the second, of the period under Constantius II. (337-360); the third, of that under Julian and Jovian taken together (360-364); the fourth, of the church under Valens (364-378); the fifth, of Theodosius the Great (379-395); the sixth, of Arcadius (395-408); and the seventh, to those years of Theodosius the Younger (408-439) which came within the period of Socrates' work.
As the title of the work ('Ekklesiastike Istoria) indicates, the subject is chiefly the vicissitudes and experiences of the Christian Church; but the author finds various reasons for interweaving with the account of ecclesiastical affairs some record also of the affairs of the state. His statement  of these reasons puts first among them the relief his readers would experience by passing from the accounts of the perpetual wranglings of bishops to something of a different character; second, the information which all ought to have on secular as well as ecclesiastical matters; and third, the interlacing of these two lines, on account of which the understanding of the one cannot be full without some knowledge of the other. By a sort of sympathy,' says he, the church takes part in the disturbances of the state,' and since the emperors became Christians, the affairs of the church have become dependent on them, and the greatest synods have been held and are held at their bidding.' It cannot be said, however, that Socrates either thoroughly realized or attempted any systematic treatment of his subject from the point of view of the true relations of church and state; he simply had the consciousness that the two spheres were not as much dissociated as one might assume.
On the general character of Socrates' History it may be said that, compared with those produced by his contemporaries, it is a work of real merit, surpassing in some respects even that of his great predecessor, Eusebius. The latter has confused his account by adopting, under the influence of his latest informant, differing versions of facts already narrated, without erasing the previous versions or attempting to harmonize or unify them. Compare with this feature Socrates' careful and complete revision of his first two books on obtaining new and more trustworthy information. 
In the collection of his facts Socrates everywhere tried to reach primary sources. A great portion of his work is drawn from oral tradition, the accounts given by friends and countrymen, the common, but not wild, rumors of the capital, and the transient literature of the day. Whenever he depends on such information, Socrates attempts to reach as far as possible the accounts of eye-witnesses,  and appends any doubts he may have as to the truth of the statements they make. Of written works he has used for the period where his work and that of Eusebius overlap the latter's Ecclesiastical History and Life of Constantine;  for other events he follows Rufinus,  abandoning him, however, in his second edition, whenever he conflicts with more trustworthy authorities. He has also made use of Archelaus' Acts,  of Sabinus' Collection of the Acts of the Synods, which he criticises for unfairness,  Epiphanius' Ancoratus,  George of Laodicea,  Athanasius' Apolog.,  de Syn.,  and de Decr. Nic.,  Evagrius,  Palladius,  Nestorius,  and Origen.  Christian writers before Origen are known to him and mentioned by him, such as Irenæus, Clement of Alexandria, Apollinaris the Elder, Serapion, and others; but he does not seem to have used their works as sources, probably because they threw no light on the subject at hand, his period being entirely different from that in which they flourished. Besides these writers, Socrates has also used public documents, pastoral and episcopal letters, decrees, acts, and other documents not previously incorporated in written works. Some of these the author has used, but does not quote in extenso, on account of their length.  Of the sources that he might have used, but has not, may be mentioned Dexippus, Eunapius (chronike historia), Olympiodorus (logoi historikoi), and especially Zosimus, his contemporary (historia nea). Whether these were unknown to him, or whether he deemed it unnecessary to make use of the information given by them, or considered them untrustworthy, it cannot be ascertained. It is sufficient to say that for the period he covers, and the geographical limitation he has put on his work, his array of facts is sufficiently large and to the purpose. The use he makes of these facts also shows sufficiently the historian as thorough as he could be considering the time and environment in which he flourished. There is an evident attempt throughout his work at precision. He marks the succession of bishops, the years in which each event took place by the consulships and Olympiads of Roman and Greek history. He has made painstaking investigations on various topics, such as the different usages in various localities, respecting the observance of Easter, the performance of the rites of baptism and marriage, the manner of fasting, of church assemblies, and other ecclesiastical usages.  His accuracy has been questioned from the time of Photius  to our own days. It cannot be denied that there are a number of errors in the History. He confused Maximian and Maximin.  He ascribes three Creeds' to the first Council of Sirmium, whereas these belonged to other councils. In general he is confused on the individuals to whom he ascribes the authorship of the Sirmian creeds.  Similar confusion and lack of trustworthiness is noticed in his version of the sufferings of Paul of Constantinople and the vicissitudes of the life of Athanasius. He has wrongly given the number of those who dissented from the decision of the Council of Nicæa as five. The letter of the Council only mentions two, -- Theonas and Secundus. The exile of Eusebius and Theognis is ascribed to a later period and a different cause by Jerome and Philostorgius, and it is generally conceded that Socrates' information was erroneous on this subject also. He is incorrect on several particulars in the lives of Basil and Gregory of Nazianzus, as also in assigning the attack at night on the church of St. Theonas to the usurpation of Gregory, the Arian bishop of Alexandria. 
The chronology of Socrates is generally accurate to about the beginning of the sixth book, or the year 398. A number of errors are found in it after that. But even before the date named, the dates of the Council of Sardica (347) and of the death of Athanasius (373, for which Socrates gives 371) are given wrong. St. Polycarp's martyrdom is also put out of its proper place by about one hundred years.  Valens' stay at Antioch and persecution of the orthodox is put too early.  The Olympiads are given wrong. 
Socrates is generally ignorant of the affairs of the Western Church. He gives a cursory account of Ambrose, but says nothing of the great Augustine, or even of the Donatist controversy, in spite of all its significance and also of the extreme probability that he knew of it; as Pelagius and Celestius, who traveled in the East about this time, could not but have made the Eastern Church acquainted with its details. In speaking of the Arian council of Antioch in 341, he seems to think that the Roman bishop had a sort of veto-power over the decisions of Occidental councils. The only legitimate inference, however, from the language of the bishop's claim is that he thought he had a right to be invited to attend in common with the other bishops of Italy.  So, again, on the duration of the fast preceding Easter among the western churches, he makes the mistaken statement that it was three weeks, and that Saturdays and Sundays were excepted.
Finally, the credence which Socrates gives to stories of miracles and portents must be noted as a blemish in his history. On the other hand, he was certainly not more credulous than his contemporaries in this respect; many of them, if we are to judge from Sozomen as an illustration, were much more so. The age was not accustomed to sifting accounts critically with a view to the elimination of the untrue. Socrates shows in this respect the historical instinct in the matter of distinguishing between various degrees of probability and credibility, but does not seem to exercise this instinct in dealing with accounts of the prodigious.
To offset these faults we must take account, on the other hand, of the persistent and successful attempt of our historian at impartiality. Of all the Christian writers of his day he is the fairest towards those who differed from the creed of his church. No one else has done justice to Julian,  or to the various heretical sects of the day, as Socrates has. To avoid even the appearance of partiality, he makes a rule for himself not to speak in terms of praise of any living person;  and it must be said that he faithfully observes this rule, making but one exception in favor of the emperor Theodosius the Younger.  Of this prince he gives a eulogistic picture, altogether different from the representations universally found in the other historians of the age.  His independence of judgment is more signally manifested in his estimates of ecclesiastics, especially the more prominent ones,  bordering at times on unjust severity. In short,' says Harnack, summing up his estimate of Socrates, the rule to be applied to Socrates is that his learning and knowledge can be trusted only a little, but his good will and straightforwardness a great deal. Considering the circumstances under which he wrote and the miseries of the times, it can only be matter for congratulation that such a man should have been our informant and that his work has been preserved to us.' 
Socrates' style is characterized by simplicity and perspicuity. From the very start he informs us that he is about to make a new departure in this respect.  Eusebius' language was not entirely satisfactory to him, nor that of older writers.  Hence his own attempt everywhere at plain, unadorned expression. The criticism of Photius,  that Socrates' style had nothing remarkable about it,' although made in the spirit of censure, is true, and according to Socrates' standard (which is also that of modern times) amounts to a commendation. Socrates, however, was not lacking in good humor and satire,  as well as in appreciation of short and pithy utterances; he often quotes proverbs and epigrammatic sayings,  and knows the influence of the anecdote and reminiscence in interesting the reader.
The value of Socrates' History cannot be overestimated. It will always remain a source of primary importance. Though, as already noted, its ideal as a history is below that set up by Thucydides, Tacitus, and others of an earlier age, -- below even that of Eusebius, -- yet as a collection of facts and documents in regard to some of the most important events of the church's life it is invaluable. Its account of the great Arian controversy, its details of the Councils of Nicæa, Chalcedon, Constantinople, and Ephesus, besides those of the lesser, local conventions, its biographical items relative to the lives of the emperors, the bishops, and monks -- some of whom are of pivotal importance in the movements of the times, its sketches of Ulphilas and Hypatia, its record of the manner and time of the conversion of the Saracens, the Goths, the Burgundians, the Iberians, and the Persians, as well as of the persecution of the Jews, the paschal controversy, not to mention a vast number of other details of minor importance, will always be read and used with the deepest interest by lovers of ecclesiastical history.
 That this was not due to a general conviction that one history of a period rendered another of the same period unnecessary is evident from the fact that the period immediately succeeding is treated of by three successive historians, and that the second of these, at least, knows and uses the work of his predecessor.  Harnack, however, successfully proves that Socrates' ideal of history, in spite of his love for it, was far from being the scientific idea which existed among pagan writers even of the age preceding his own. Cf. Herzog-Plitt, Real-Encyk. Vol. 14, p. 413 sq.  VI. 1.  Cf. II. 1; VI. Int.; VII. 47. This Theodorus is simply addressed as hiere tou theou anthrope, from which it has been rightly inferred that he was an ordained presbyter. The view that Theodore of Mopsuestia is the person addressed has been proved to be erroneous from the date of his death, 429 a.d. The Ecclesiastical History was no doubt completed after that event, and could not have contained an address to the eminent Theodore.  VII. 47.  V. Int.  II. 1. The new information here referred to is drawn from the works of Athanasius, which had come into the hands of the author. Cf. II. 17.  I. Int.; V. 19; VI. Int.  I. 8.  I. 12, 19; II. 1; III. 19; IV. 24, 26.  I. 22.  I. 8; II. 15, 17, 20; III. 10, 25; IV. 12, 22.  V. 24.  I. 24.  II. 28; III. 8.  II. 37.  VI. 13.  III. 7.  IV. 23.  VII. 19-24.  III. 7.  II. 17.  V. 22.  Phot. Biblioth. Cod. 28. alla kai en tois dogmasi ou lian akribes. Whether in this phrase he meant to accuse Socrates with inaccuracy in the narration of facts or indifference to theological dogma is not very clear. Probably the former.  I. 2.  II. 30.  II. 11.  V. 22.  IV. 17.  On the chronology of Socrates, see Harnack and Jeep.  II. 8 and 17.  III. 1, 12, 14, 21, 23.  VI. Int.  VII. 22.  Cf. Sozomen, IX. 1, and Gibbon, IV. 163.  Cf. attitude towards Chrysostom and Cyril of Alexandria, above alluded to; also his censure of pride and contention among members of the clergy. See V. Int. 15, 23; VI. 6; VII. 11, 29.  In Encycl. Britan.  I. 1, ou phraseos onkou phrontizontes ; so in III. 1, medeis epizeteito kompon phraseos; and VI. Int., Isthi de hemas me espoudakenai peri ten phrasin, where he adds that if he had attempted a different style, he might have failed of his purpose of writing a popular history.  VI. 22; VII. 27.  Biblioth. Cod. 28.  III. 16; IV. 22; VI. 13; VII. 21, 34.  II. 8; III. 21; V. 15; VII. 29, 31.
 Harnack, however, successfully proves that Socrates' ideal of history, in spite of his love for it, was far from being the scientific idea which existed among pagan writers even of the age preceding his own. Cf. Herzog-Plitt, Real-Encyk. Vol. 14, p. 413 sq.
 VI. 1.
 Cf. II. 1; VI. Int.; VII. 47. This Theodorus is simply addressed as hiere tou theou anthrope, from which it has been rightly inferred that he was an ordained presbyter. The view that Theodore of Mopsuestia is the person addressed has been proved to be erroneous from the date of his death, 429 a.d. The Ecclesiastical History was no doubt completed after that event, and could not have contained an address to the eminent Theodore.
 VII. 47.
 V. Int.
 II. 1. The new information here referred to is drawn from the works of Athanasius, which had come into the hands of the author. Cf. II. 17.
 I. Int.; V. 19; VI. Int.
 I. 8.
 I. 12, 19; II. 1; III. 19; IV. 24, 26.
 I. 22.
 I. 8; II. 15, 17, 20; III. 10, 25; IV. 12, 22.
 V. 24.
 I. 24.
 II. 28; III. 8.
 II. 37.
 VI. 13.
 III. 7.
 IV. 23.
 VII. 19-24.
 III. 7.
 II. 17.
 V. 22.
 Phot. Biblioth. Cod. 28. alla kai en tois dogmasi ou lian akribes. Whether in this phrase he meant to accuse Socrates with inaccuracy in the narration of facts or indifference to theological dogma is not very clear. Probably the former.
 I. 2.
 II. 30.
 II. 11.
 V. 22.
 IV. 17.
 On the chronology of Socrates, see Harnack and Jeep.
 II. 8 and 17.
 III. 1, 12, 14, 21, 23.
 VI. Int.
 VII. 22.
 Cf. Sozomen, IX. 1, and Gibbon, IV. 163.
 Cf. attitude towards Chrysostom and Cyril of Alexandria, above alluded to; also his censure of pride and contention among members of the clergy. See V. Int. 15, 23; VI. 6; VII. 11, 29.
 In Encycl. Britan.
 I. 1, ou phraseos onkou phrontizontes ; so in III. 1, medeis epizeteito kompon phraseos; and VI. Int., Isthi de hemas me espoudakenai peri ten phrasin, where he adds that if he had attempted a different style, he might have failed of his purpose of writing a popular history.
 VI. 22; VII. 27.
 Biblioth. Cod. 28.
 III. 16; IV. 22; VI. 13; VII. 21, 34.
 II. 8; III. 21; V. 15; VII. 29, 31.