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 IV of Jerusalem support of Agnes and her husband Reginald of Sidon, Raymond, and many of the other barons, excluding Sibylla from the succession. Raymond was to act as guardian of the infant heir, and later as regent if Baldwin IV was to expire, but Baldwin IV himself would continue to rule. The child was crowned co-king as Baldwin V on November 20, 1183. In the early months of 1184, Baldwin attempted to have the marriage between Sibylla and Guy annulled. This was foiled by their holding fast in Ascalon, Guy refusing to attend the annulment proceedings. The military expedition to relieve Karak