Sabinus’ Collection of the Acts of the Synods, which he criticises for unfairness,72 Epiphanius’ Ancoratus,73 George of Laodicea,74 Athanasius’ Apolog.,75 de Syn.,76 and de Decr. Nic.,77 xvi Evagrius,78 Palladius,79 Nestorius,80 and Origen.81 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.82 Of the sources that he might have used, but has not, may be mentioned Dexippus, Eunapius (χρονικὴ ἱστορία), Olympiodorus (λόγοι ἱστορικοί), and especially Zosimus, his contemporary (ἱστορία νέα). 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.83 His accuracy has been questioned from 72 I. 8; II. 15, 17, 20; III. 10, 25; IV. 12, 22. 73 V. 24. 74 I. 24. 75 II. 28; III. 8. 76 II. 37. 77 VI. 13. 78 III. 7. 79 IV. 23. 80 VII. 19–24. 81 III. 7. 82 II. 17. 83 V. 22. 16 Socrates' Ecclesiastical History.