[6] To secure the succession to the ailing king, his sister, Sibylla, was given in marriage to William of Montferrat in November 1176, but he died seven months later.

[16][17] The first group included the mother of Baldwin IV and Sibylla, Agnes of Courtenay, her brother, Joscelin, and Raynald of Châtillon, Lord of Oultrejordain.

[16] To secure Guy's position, the king arranged the betrothal of Isabella to Raynald of Châtillon's stepson, Humphrey IV of Toron in October 1180.

[22] Guy's principal supporters, Joscelin of Courtenay and Raynald of Châtillon, were not present at Baldwin V's coronation, because they attended the wedding of Isabella and Humphrey of Toron.

[24] According to Ernoul's chronicle, Stephanie of Milly sent meals to the besiegers from the feast and Saladin forbade his engineers to destroy the tower of the fortress in which Humphrey and Isabella spent the wedding night.

And when Saladin received these gifts he was exceedingly delighted and gave thanks to those who brought them to him, asking where the bride and bridegroom were staying: their tower was pointed out to him.

[29][30] On Raymond's demand, the High Court of Jerusalem ruled that a committee consisting of the pope, the Holy Roman Emperor and the kings of France and England would be entitled to choose between Sibylla and Isabella if Baldwin V died before reaching the age of majority.

[32][33] Sibylla's uncle Joscelin of Courtenay persuaded Raymond III of Tripoli and his allies to leave Jerusalem, and urged her supporters (including Raynald of Châtillon) to assemble in the town.

[33] Ignoring the 1185 ruling of the High Court, the noblemen and prelates who came to Jerusalem concluded that Sibylla was the lawful heir to her son.

[35] On Raymond of Tripoli's proposal, the noblemen who assembled in Nablus decided that they proclaim Isabella and Humphrey of Toron queen and king.

[42] Tyre was an exception, holding out for months under the command of Conrad of Montferrat who had come to the Holy Land from Italy a few weeks after the battle.

[44][45] Guy laid siege to Acre, but James of Avesnes, Louis III of Thuringia and other crusader commanders who came to the Holy Land also questioned his claim to leadership.

[53] Maria Komnena also swore that Baldwin IV had forced the eight-year-old Isabella to marry Humphrey of Toron, whose effeminacy was well known.

[54] Before long, the papal legate, Ubaldo Lanfranchi, Archbishop of Pisa, and Philip of Dreux, Bishop of Beauvais, annulled the marriage of Isabella and Humphrey.

[62] After Richard decided to return to England in April 1192, the barons urged him to revise the previous decision about the Kingdom of Jerusalem.

[63] Richard dispatched his nephew Count Henry II of Champagne to inform Conrad about the barons' decision.

[64] When Duke Hugh III of Burgundy, the French king's lieutenant in the Holy Land, urged Isabella to deliver Tyre to him, she shut herself up in the fortress and refused to open its gates.

[69] Henry, who was the nephew of both Richard of England and Philip of France, was acclaimed king by the barons and the citizens of Tyre.

[71] The barons and the citizens, continued Ernoul, promised him that his children would inherit the Kingdom of Jerusalem to convince him to accept the crown.

King Aimery died in 1205 of food poisoning caused by white mullet, four days before his wife, and shortly after their son.

The legality of Isabella's divorce from Humphrey was challenged in 1213, during the dispute over the succession to Champagne between her daughters Alice and Philippa and Henry's nephew Theobald IV.

However, its validity seems to have been upheld: no challenge was made to the legitimacy of Maria and her descendants to succeed to the throne of Jerusalem, and in Champagne, Theobald bought off his cousins Alice and Philippa.

Shelby implies that Isabella plotted Conrad's murder in revenge for his abuse, and depicts her as mentally numbed and indifferent to Henry.

She is the title character of Alan Gordon's mystery novel, The Widow of Jerusalem (2003), which paints a more sympathetic portrait of her marriage to Conrad.