William remained archbishop of Tyre and chancellor of the kingdom, but the details of his life at this time are obscure.
The 13th-century continuators claim that Heraclius excommunicated William in 1183, but it is unknown why Heraclius would have done this.
They also claim that William went to Rome to appeal to the Pope, where Heraclius had him poisoned.
According to Peter Edbury and John Rowe, the obscurity of William's life during these years shows that he did not play a large political role, but concentrated on ecclesiastical affairs and the writing of his history.
The story of his excommunication, and the unlikely detail that he was poisoned, were probably an invention of the Old French continuators.
William remained in the kingdom and continued to write up until 1184, but by then Jerusalem was internally divided by political factions and externally surrounded by the forces of Saladin, and "the only subjects that present themselves are the disasters of a sorrowing country and its manifold misfortunes, themes which can serve only to draw forth lamentations and tears."

His importance had dwindled with the victory of Agnes and her supporters, and with the accession of Baldwin V, infant son of Sibylla and William of Montferrat.
Baldwin was a sickly child and he died the next year.
In 1186 he was succeeded by his mother Sibylla and her second husband Guy of Lusignan, ruling jointly.
William was probably in failing health by this point.
Rudolf Hiestand discovered that the date of William's death was 29 September, but the year was not recorded; whatever the year, there was a new chancellor in May 1185 and a new archbishop of Tyre by 21 October 1186.
Hans E. Mayer concluded that William died in 1186, and this is the year generally accepted by scholars.

William's foresight about the misfortunes of his country was proven correct less than a year later.
Saladin defeated King Guy at the Battle of Hattin in 1187, and went on to capture Jerusalem and almost every other city of the kingdom, except the seat of William's archdiocese, Tyre.
News of the fall of Jerusalem shocked Europe and plans were made to send assistance.
According to Roger of Wendover, William was present at Gisors in France in 1188 when Henry II of England and Philip II of France agreed to go on crusade: "Thereupon the king of the English first took the sign of the cross at the hands of the Archbishop of Rheims and William of Tyre, the latter of whom had been entrusted by our lord the pope with the office of legate in the affairs of the crusade in the western part of Europe."
Roger was however mistaken; he knew that an unnamed archbishop of Tyre was present and assumed it must have been the William whose chronicle he possessed, although the archbishop in question was actually William's successor Joscius.
William remained archbishop of Tyre and chancellor of the kingdom, but the details of his life at this time are obscure. The 13th-century continuators claim that Heraclius excommunicated William in 1183, but it is unknown why Heraclius would have done this. They also claim that William went to Rome to appeal to the Pope, where Heraclius had him poisoned. According to Peter Edbury and John Rowe, the obscurity of William's life during these years shows that he did not play a large political role, but concentrated on ecclesiastical affairs and the writing of his history. The story of his excommunication, and the unlikely detail that he was poisoned, were probably an invention of the Old French continuators. William remained in the kingdom and continued to write up until 1184, but by then Jerusalem was internally divided by political factions and externally surrounded by the forces of Saladin, and "the only subjects that present themselves are the disasters of a sorrowing country and its manifold misfortunes, themes which can serve only to draw forth lamentations and tears."
His importance had dwindled with the victory of Agnes and her supporters, and with the accession of Baldwin V, infant son of Sibylla and William of Montferrat. Baldwin was a sickly child and he died the next year. In 1186 he was succeeded by his mother Sibylla and her second husband Guy of Lusignan, ruling jointly. William was probably in failing health by this point. Rudolf Hiestand discovered that the date of William's death was 29 September, but the year was not recorded; whatever the year, there was a new chancellor in May 1185 and a new archbishop of Tyre by 21 October 1186. Hans E. Mayer concluded that William died in 1186, and this is the year generally accepted by scholars.
William's foresight about the misfortunes of his country was proven correct less than a year later. Saladin defeated King Guy at the Battle of Hattin in 1187, and went on to capture Jerusalem and almost every other city of the kingdom, except the seat of William's archdiocese, Tyre. News of the fall of Jerusalem shocked Europe and plans were made to send assistance. According to Roger of Wendover, William was present at Gisors in France in 1188 when Henry II of England and Philip II of France agreed to go on crusade: "Thereupon the king of the English first took the sign of the cross at the hands of the Archbishop of Rheims and William of Tyre, the latter of whom had been entrusted by our lord the pope with the office of legate in the affairs of the crusade in the western part of Europe." Roger was however mistaken; he knew that an unnamed archbishop of Tyre was present and assumed it must have been the William whose chronicle he possessed, although the archbishop in question was actually William's successor Joscius.
William of Tyre