William of Tyre in the context of "Frisian participation in the Crusades"

The Estoire d'Eracles ("History of Heraclius") is an anonymous Old French translation and continuation of the Latin History of Deeds Done Beyond the Sea by William of Tyre. It begins with recapture of Jerusalem by the Roman emperor Heraclius in AD 630, from which it takes its name, and continues down to 1184. The continuation recounts the history of the Crusader states from Saladin's capture of Jerusalem in 1187 down to 1277.

The translation was made between 1205 and 1234, possibly in Western Europe. Several times the text of the translation was changed and the manuscripts preserve different versions of William's text. The continuations were added to the translation between 1220 and 1277. There are two different versions of the first continuation, covering the years 1185–1225. Both reflect the political attitudes of the Crusader aristocracy. There are 49 surviving manuscripts of the Eracles. Of these, 44 contain a first continuation drawn from the Chronicle of Ernoul and five (the so-called Colbert–Fontainebleau manuscripts) contain a different version. Twelve of the manuscripts contain a unique continuation for the years 1229–1261 drawn from the independent work known as the Rothelin Continuation.

Baldwin IV (1161–1185), known as the Leper King, was the king of Jerusalem from 1174 until his death in 1185. Baldwin ascended to the throne when he was thirteen despite having leprosy. He launched several attempts to curb the increasing power of the ruler of Egypt, Saladin, though much of his life was marked by infighting amongst the kingdom's nobles. Throughout his reign, and especially at the end of his life, he was troubled by his succession, working to select a suitable heir and prevent a succession crisis. Choosing competent advisers, Baldwin ruled a thriving crusader state, protecting it from Saladin.

Baldwin's parents, King Amalric and Agnes of Courtenay, separated when Baldwin was two. At nine years old, he was sent to be educated by Archbishop William of Tyre. William noticed preliminary symptoms of leprosy, but Baldwin was only diagnosed after he succeeded his father as king. Thereafter, his hands and face became increasingly disfigured. He mastered horse riding despite gradually losing sensation in his extremities and fought in battles until his last years. First, Miles of Plancy ruled the kingdom in Baldwin's name, then Count Raymond III of Tripoli took over until the king reached the age of majority in 1176. Baldwin's mother then returned to court, and he became closer to her and her brother, Joscelin.