Boniface I, Marquess of Montferrat the independent city communes of the Lombard League. Boniface's eldest brother, William, had died in 1177, soon after marrying Sibylla, the heiress presumptive to the Kingdom of Jerusalem. In 1179, the Byzantine emperor Manuel I Comnenus offered his daughter Maria Porphyrogenita as a bride to one of the sons of William V. Since Boniface, like his older brother Conrad, was already married, and Frederick was a priest, the youngest brother, Renier, married her instead, only to be murdered along with her during the usurpation of Andronicus. In 1183, Boniface's nephew Baldwin V was crowned co-king of Jerusalem. William V went
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