Synods form a noticeable feature in the history of the general Church. Particular synods have served to indicate particular stages in the progress or retrogression of the life of the Church, as respects the development of knowledge and teaching, the formation of the worship and the constitution of the Church itself; and all synods serve, more clearly than other institutions, to reveal the ruling spirit, the measure of strength, or the type of disease, in any given period. The breadth of the field covered by this title will appear from the fact that Mansi's (q.v.) collection of the acts, etc., of councils, extending only into the 15th century, embraces 31 volumes folio.
With respect to the origin of synods opinions differ. Some authors hold them to have been divinely instituted through the agency of the apostles (Acts 15 especially ver. 28, "It seemed good to the Holy Ghost, and to us"), while others concede to them a merely accidental rise. The council in Acts 15 must certainly be considered a synod, though it does not appear that it was designed to introduce a permanent institution. On the other hand, the situation of the Church and the progress of events furnished the providential conditions by which ecclesiastical assemblies became necessary, so that- the theory of a merely human origin for them cannot be accepted. The history of our subject, excluding the period since the Reformation, admits of being divided into five periods.
I. The Beginnings of the Institution of Synods as Furnished by Provincial Synods (to A.D. 325). — The earliest of such synods of which mention is made are one alleged to have been held in Sicily in A.D. 125 against the gnostic Heracleon (q.v.), and one at Rome under bishop Telesphorus (d. 139); but there is not the slightest evidence that either of them was held. The earliest of which we have authentic information were held in Asia Minor against the Montanists (Eusebius, Hist. Eccl. 5, 16), probably not before A.D. 150. Soon afterwards various synods were held to discuss the celebration of Easter (ibid. 5, 23) and other questions; so that Tertullian speaks (De Jejuniis, c. 13) of the convening of such bodies as a custom among the Greeks, and thereby at the same time implies that such assemblies were not known in his own (African) Church.
Such conferences promoted Christian unity and laid the foundation for a government of the churches by superior authority. By the middle of the 3rd century synods were regularly held in each year, and were attended by bishops and elders, so that they had already become a fixed and periodically recurring institution, in which the different churches shared in the persons of their appropriate representatives (see Firmilian's letter to Cyprian, Epp. No. 75). The earliest synods in the West were held in Africa about A.D. 215, and soon such assemblies became frequent. The next stage in the development of synods appears in the extension of their jurisdiction over larger areas than a single district or province, by which the inauguration of ecumenical councils was prepared for. At Iconium in 256, representatives were present from Galatia, Cilicia, etc. Every part of Spain was represented at Elvira; and the Synod of Aries, in 314, was attended by bishops from Gaul, Britain, Germany, Spain, North Africa, and Italy.
II. A.D. 325 to 869. —The ecumenical synods of the Greek Church, beginning with that of Nicaea (q.v.) and closing with the fourth Council of Constantinople (q.v.).
III. A.D. 869 to 1311. —Councils of the Western Church under the direction of the papacy, including a great number of provincial and national synods whose proceedings indicated both the utmost devotion and the most decided opposition to the rule of the popes-ending with the general Council of Vienne in Gaul (q.v. severally).
IV. A.D. 1311 to 1517. —Councils ostensibly aiming to secure reform "in head and members" Pisa, Constance, and Basle (q.v. severally).
V. A.D. 1517 to' 1563. —The Reformation and the reactionary Synod of Trent (q.v.).
For an enumeration and characterization of the more important synods see the article COUNCILS SEE COUNCILS , to which we also refer for a list of sources. —Herzog, Real-Encyklop. s.v.