Isabella I of Jerusalem tried to play Isabella and her husband off against him, but Humphrey did homage to the royal couple. Isabella was the daughter of Amalric, King of Jerusalem, by his second wife, Maria Comnena. Maria Comnena (who was a grandniece of the Byzantine Emperor, Manuel I Komnenos) married Amalric on 29 August 1171. Isabella was born before September 1172. Amalric died unexpectedly on 11 July 1174. His son by his first marriage, Baldwin IV, was crowned king two weeks later. Before long, it became obvious that Baldwin suffered from lepromatous leprosy. To secure the succession of the ailing king, his sister,
Baldwin I of Jerusalem his adoptive father, but he did nothing when the rioters broke into the citadel on 9March. Thoros and his wife were captured and murdered. On the following day, the townspeople acknowledged Baldwin as their ruler (or "doux"). He assumed the title of count and established the first crusader state. The Seljuqs had captured Edessa from the Byzantines in 1087, but Alexios I Komnenos did not demand that Baldwin hand over the town. MacEvitt argues that the local population did not regard Baldwin's ascension as "a change in regime, but the replacement of one strongman with vague Byzantine ties with another