In the second half of the twelfth century, English interest in the Holy Land was intimately linked to the dynastic claims of the Angevin kings. Historians and hagiographers writing in the shadow of the Angevin court deliberately shaped a narrative of Angevin rule that laid claim to the royal legacy of Britain, the imperial legacy of Rome, and the spiritual legacy of Jerusalem. In particular, these writers reimagined legends about the Roman emperor Constantine the Great (r. 306–337) and his mother, Helena Augusta (d. 328/9), in ways that turned them into exemplary twelfth-century English monarchs. This process of reimagining, I argue, had two distinct phases. In the middle decades of the twelfth century, Anglo-Norman authors drew upon Helena's and Constantine's legacies in Britain to legitimize Henry II's (r. 1154–1189) right to rule England. By the beginning of the thirteenth century, in turn, Angevin depictions of Britain's fourth-century Roman rulers began to show influences from the memory of events surrounding the Third Crusade (in particular the Muslims’ capture of the True Cross and Jerusalem in 1187) and of English participation in the crusading movement. While a Christian longing to protect the sacred sites and relics of the Holy Land from the Muslims was felt throughout Europe, in England that longing took the shape of a distinctive crusading ideology built upon the Angevins’ appropriation of England's Romano-British past – a past to which the Angevin kings sought to connect themselves through genealogy and cultural inheritance.

While Angevin interest in Roman Britain took many forms, the legends about Helena and Constantine proved especially adaptable to twelfth-century events. Helena's historic connection to Britain was tenuous at best. She was probably born somewhere in Asia Minor and may have been an innkeeper or a prostitute before she became the wife (or, more likely, the consort) of the Roman tetrarch Constantius Chlorus (r. 293–306). Their son, the future emperor Constantine the Great, was born in Naissus (present-day Niš, Serbia) around 272. Constantius later separated from Helena in 298 so that he could marry Theodora, the daughter of his senior emperor Maximian. It was through Constantius, however, that Helena's story first became linked with the history of Roman Britain. Under the Tetrarchy, Constantius was responsible for ruling the provinces of Gaul and Britannia.