Kadi Burhan al-Din, a learned Islamic jurist and poet, had risen to power under the latter-day Eretnid rulers of north-eastern Anatolia, before supplanting them altogether and declaring himself sultan at Sivas in 1381/82.[1] During the same period, the nascent Ottoman Empire, under Murad I (r. 1362–1389), began its expansion from northwestern Anatolia into the central and eastern parts of the peninsula. This expansion was, in the words of historian Dimitris Kastritsis, "generally justified through marriage alliances and other diplomatic means."[2]