also agrees, and Augusti is of the same opinion.  But Thomassinus is of a different mind, thinking, so says Hefele,  that there were "two classes of chorepiscopi, of whom the one were real bishops, while the other had only the title without consecration."
The third opinion, that they were merely presbyters, is espoused by Morinus and Du Cange, and others who are named by Bingham.  This last opinion is now all but universally rejected, to the other two we shall now devote our attention.
For the first opinion no one can speak more learnedly nor more authoritatively than Arthur West Haddon, who writes as follows;
(Haddon, Dict. Christ. Antiq. s.v. Chorepiscopus.)
The chorepiscopus was called into existence in the latter part of the third century, and first in Asia Minor, in order to meet the want of episcopal supervision in the country parts of the now enlarged dioceses without subdivision. [They are] first mentioned in the Councils of Ancyra and Neo-Cæsarea a.d.314, and again in the Council of Nice (which is subscribed by fifteen, all from Asia Minor or Syria). [They became] sufficiently important to require restriction by the time of the Council of Antioch, a.d.341; and continued to exist in the East until at least the ninth century, when they were supplanted by exarchoi. [Chorepiscopi are] first mentioned in the West in the Council of Riez, a.d.439 (the Epistles of Pope Damasus I. and of Leo. M. respecting them being forgeries), and continued there (but not in Africa, principally in France) until about the tenth century, after which the name occurs (in a decree of Pope Damasus II. ap. Sigeb. in an.1048) as equivalent to archdeacon, an office from which the Arabic Nicene canons expressly distinguish it. The functions of chorepiscopi, as well as their name, were of an episcopal, not of a presbyterial kind, although limited to minor offices. They overlooked the country district committed to them, "loco episcopi," ordaining readers, exorcists, subdeacons, but, as a rule, not deacons or presbyters (and of course not bishops), unless by express permission of their diocesan bishop. They confirmed in their own districts, and (in Gaul) are mentioned as consecrating churches (vide Du Cange). They granted eirenikai, or letters dimissory, which country presbyters were forbidden to do. They had also the honorary privilege (timomenoi ) of assisting at the celebration of the Holy Eucharist in the mother city church, which country presbyters had not (Conc. Ancyr. can. xiii.; Neo-Cæsar. can. xiv.; Antioch, can. x.; St. Basil M. Epist.181; Rab. Maur. De Instit. Cler. i.5, etc. etc.). They were held therefore to have power of ordination, but to lack jurisdiction, save subordinately. And the actual ordination of a presbyter by Timotheus, a chorepiscopus, is recorded (Pallad., Hist. Lausiac.106).
In the West, i.e. chiefly in Gaul, the order appears to have prevailed more widely, to have usurped episcopal functions without due subordination to the diocesans, and to have been also taken advantage of by idle or worldly diocesans. In consequence it seems to have aroused a strong feeling of hostility, which showed itself, first in a series of papal bulls, condemning them; headed, it is true, by two forged letters respectively of Damasus I. and Leo. M. (of which the latter is merely an interpolated version of Conc. Hispal. II. a.d.619, can.7, adding chorepiscopi to presbyteri, of which latter the council really treats), but continuing in a more genuine form, from Leo III. down to Pope Nicholas I. (to Rodolph, Archbishop of Bourges, a.d.864); the last of whom, however, takes the more moderate line of affirming chorepiscopi to be really bishops, and consequently refusing to annul their ordinations of presbyters and deacons (as previous popes had done), but orders them to keep within canonical limits; and secondly, in a series of conciliar decrees, Conc. Ratispon. a.d.800, in Capit. lib. iv. c.1, Paris. a.d.829, lib. i.c.27; Meld. a.d.845, can.44; Metens. a.d.888, can.8, and Capitul. v.168, vi.119, vii.187, 310, 323, 324, annulling all episcopal acts of chorepiscopi, and ordering them to be repeated by "true" bishops; and finally forbidding all further appointments of chorepiscopi at all.
That chorepiscopi as such -- i.e. omitting the cases of reconciled or vacant bishops above mentioned, of whose episcopate of course no question is made -- were at first truly bishops both in East and West, appears almost certain, both from their name and functions, and even from the arguments of their strong opponents just spoken of. If nothing more could be urged against them, than that the Council of Neo-Cæsarea compared them to the Seventy disciples, that the Council of Antioch authorises their consecration by a single bishop, and that they actually were so consecrated (the Antiochene decree might mean merely nomination by the word ginesthai, but the actual history seems to rule the term to intend consecration, and the [one] exceptional case of a chorepiscopus recorded [Actt. Episc. Cenoman. ap. Du Cange] in late times to have been ordained by three bishops [in order that he might be a full bishop] merely proves the general rule to the contrary) -- and that they were consecrated for "villages," contrary to canon, -- then they certainly were bishops. And Pope Nicholas expressly says that they were so. Undoubtedly they ceased to be so in the East, and were practically merged in archdeacons in the West.
For the second opinion, its great champion, Thomassinus shall speak.
(Thomassin, Ancienne et Nouvelle Discipline de l'Église, Tom. I. Livre II. chap 1. § iii.)
The chorepiscopi were not duly consecrated bishops, unless some bishop had consecrated a bishop for a town and the bishop thus ordained contrary to the canons was tolerated on condition of his submitting himself to the diocesan as though he were only a chorepiscopus. This may be gathered from the fifty-seventh canon of Laodicea.
From this canon two conclusions may be drawn, 1st. That bishops ought not to be ordained for villages, and that as Chorepiscopi could only be placed in villages they could not be bishops. 2d. That sometimes by accident a chorepiscopus might be a bishop, but only through having been canonically lowered to that rank.
The Council of Nice furnishes another example of a bishop lowered to the rank of a chorepiscopus in Canon viii. This canon shows that they should not have been bishops, for two bishops could never be in a diocese, although this might accidentally be the case when a chorepiscopus happened to be a bishop.
This is the meaning which must be given to the tenth canon of Antioch, which directs that chorepiscopi, even if they have received episcopal orders, and have been consecrated bishops, shall keep within the limits prescribed by the canon; that in cases of necessity, they ordain the lower clergy; but that they be careful not to ordain priests or deacons, because this power is absolutely reserved to the Diocesan. It must be added that as the council of Antioch commands that the Diocesan without any other bishop can ordain the chorepiscopus, the position can no longer be sustained that the chorepiscopi were bishops, such a method of consecrating a bishop being contrary to canon xix. of the same council, moreover the canon does not say the chorepiscopus is to be ordained, but uses the word genesthai by the bishop of the city (canon x.). The Council of Neocæsarea by referring them to the seventy disciples (in Canon XIV.) has shown the chorepiscopi to be only priests.
But the Council of Ancyra does furnish a difficulty, for the text seems to permit chorepiscopi to ordain priests. But the Greek text must be corrected by the ancient Latin versions. The letter attributed to pope Nicholas, a.d.864, must be considered a forgery since he recognises the chorepiscopi as real bishops.
If Harmenopulus, Aristenus, Balsamon, and Zonaras seem to accord to the chorepiscopi the power to ordain priests and deacons with the permission of the Diocesan, it is because they are explaining the meaning and setting forth the practice of the ancient councils and not the practice of their own times. But at all events it is past all doubt that before the seventh century there were, by different accidents, chorepiscopi who were really bishops and that these could, with the consent of the diocesan, ordain priests. But at the time these authors wrote, there was not a single chorepiscopus in the entire East, as Balsamon frankly admits in commenting on Canon xiii. of Ancyra.
Whether in the foregoing the reader will think Thomassinus has proved his point, I do not know, but so far as the position of the chorepiscopi in synods is concerned there can be no doubt whatever, and I shall allow Hefele to speak on this point.
(Hefele, History of the Councils, Vol. I. pp.17, 18.)
The Chorepiscopi (chorepiskopoi), or bishops of country places, seem to have been considered in ancient times as quite on a par with the other bishops, as far as their position in synod was concerned. We meet with them at the Councils of Neocæsarea in the year 314, of Nicæa in 325, of Ephesus in 431. On the other hand, among the 600 bishops of the fourth Ecumenical Council at Chalcedon in 451, there is no chorepiscopus present, for by this time the office had been abolished; but in the Middle Ages we again meet with chorepiscopi of a new kind at Western councils, particularly at those of the French Church, at Langres in 830, at Mayence in 847, at Pontion in 876, at Lyons in 886, at Douzy in 871.
 Binterim, Denkwürdigkeiten, vol. i. part ii.-pp. 386-414.  Augusti, Denkwürdigkeiten, vol. xi. p. 159 et seqq.  Hefele, Hist. of the Councils, vol. ii.[p. 322.  Bingham, Antiquities, ii. xiv. 2, 3.
 Augusti, Denkwürdigkeiten, vol. xi. p. 159 et seqq.
 Hefele, Hist. of the Councils, vol. ii.[p. 322.
 Bingham, Antiquities, ii. xiv. 2, 3.