Keratsa of Bulgaria

In 1340, she was born to Tsar Ivan Alexander of Bulgaria and his second wife, Sarah-Theodora. On 17 August 1355, Keratsa was betrothed to the junior emperor Andronikos Palaiologos. The marital document issued by the Patriarchate stated that "it would be beneficial to the Christians: Byzantines and Bulgarians, and pernicious to the [the Turks]."

In 1373, while still co-emperor with his father, John V Palaiologos, Andronikos tried to usurp the throne when the Ottoman sultan Murad II forced John V to become a vassal. As a result, Keratsa (along with Andronikos and their son) were imprisoned for three years, until they were liberated by the Genoese. On 12 August 1376, Andronikos IV deposed his father and replaced him as Emperor, with Keratsa as his Empress-consort. The new imperial couple remained in control of Constantinople until 1 July 1379, when John V was restored to his throne. Andronikos IV was reappointed to co-emperor in May 1381 and was given Selymbria to govern, but hostile tensions between John V and Andronikos IV lasted until the death of the latter in 1385.

Keratsa spent the later part of her life as a nun under the name Mathissa. She died in 1390.

Keratsa and Andronikos IV Palaiologos had three children, a son and two daughters. Their son became emperor John VII Palaiologos, reigning for five months in 1390 and again from 1403 &ndash: 1408 in Thessalonica.