Athanasius I, (1230 - October 28, 1310) was the Ecumenical Patriarch of Constantinople for two periods from 1289 to 1293 and 1303 to 1309. He was born in Adrianople and died in Constantinople. Chosen by the emperor Andronicus II Palaeologus as patriarch, he opposed the reunion of the Greek and Roman Churches and introduced an ecclesial reform that evoked opposition within the clergy. He resigned in 1293 and was restored in 1303 with popular support. The pro-union clergical faction forced him into retirement in early 1310.