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 of Ibelin as her consort. The Ibelins and Raymond favoured the accession of Isabella, but Humphrey refused to be crowned and cause a civil war, and instead swore allegiance to Sibylla and Guy. All the other barons of the kingdom paid homage to Guy as well, except for Raymond and Baldwin. Baldwin placed his young son Thomas under the care of his brother Balian, and exiled himself to the Principality of Antioch, where he was welcomed with great fanfare. Baldwin considered Guy "a madman and a fool", and refused to pay homage because his father had not paid homage to Guy's father