First Council of Nicaea
Constantine had invited all 1800 bishops of the Christian church (about 1000 in the east and 800 in the west), but only 250 to 320 bishops actually participated. Eusebius of Caesarea counted 250, Athanasius of Alexandria counted 318, and Eustathius of Antioch counted 270 (all three were present at the council). Later, Socrates Scholasticus recorded more than 300, and Evagrius, Hilarius, Jerome and Rufinus recorded 318.