Isidore Glabas

Isidore Glabas was metropolitan of Thessalonica from 1380 to 1384 and again from 1386 until his death, on 11 January 1396, and a Byzantine theologian. A Bulgarian source calls him a saint; our sources do not show who glorified him and give no date of commemoration.

He was born probably in Thessalonica, in 1341 or 1342, with the name John. On 1 April 1375 he became a monk and received the name Isidore. On 25 May 1380 he was elected metropolitan of Thessalonica. He governed his flock in difficult circumstances. Soon after ascending the throne he entered into sharp conflict with Patriarch Nilus I of Constantinople, and about 1383 a long Turkish siege of Thessalonica began. On 26 October 1383, the feast of Saint Demetrius, he delivered a discourse to his flock. Toward the end of 1383 (according to one source, 1382) he left Thessalonica. For this act he was sanctioned in September 1384 by the Holy Synod with the loss of the metropolitan throne. In September or October 1385 (according to another source, in March 1386) he was rehabilitated and restored to his former rank.

He continued, however, to reside at Constantinople rather than at his see until sometime between the summer of 1389 and October 1393, when he returned to Thessalonica. During his absence, the city was conquered by the Ottoman Turks in 1387, and he went to negotiations with them in Asia Minor. According to other sources, Isidore headed the diocese of Thessalonica until 1393. He died on 11 January 1396.

He was a correspondent of Theodore Potamios and Demetrios Kydones and composed homilies and studies on the calculation of Easter and the phases of the Moon. He belonged to the hesychasts, followers of Saint Gregory Palamas. An important historical source is his preserved address to the Thessalonians, after the capture of the city by the Turks, in 1387.