Christianity would die without Islam.

[Minimalist]

Not even close.

The fucking church had been shoving jesus up the barbarians' asses for a long time prior to the 8th century.

http://en.wikipedia.org/wiki/Clovis_I#Catholic_king

Catholic king

Clovis had previously married the Catholic Burgundian princess Clotilde (later canonized as St. Clotilde), and, according to Gregory of Tours, as a result of his victory at Tolbiac (traditionally set in 496), he converted to her Catholic faith. Before his conversion he had been adamant about not converting from his pagan religion to Christianity. Clotilde had wanted her son to be baptized but Clovis refused to allow it, so Clotilde had the child baptized without Clovis's knowledge. Shortly after his baptism, their son died, and his death further strengthened Clovis's resistance to converting to Christianity. Clotilde also had their second son baptized without her husband's permission, and this son got very ill and nearly died after his baptism.[9] Yet Christianity did offer certain advantages to Clovis as he fought to distinguish his rule among many competing power centers in western Europe. His conversion to the Roman Catholic form of Christianity served to set him apart from the other Germanic kings of his time, such as those of the Visigoths and the Vandals, who had converted from pagan beliefs to Arian Christianity. His embrace of the Roman Catholic faith may also gained him the support of the Catholic Gallo-Roman aristocracy in his later campaign against the Visigoths, which drove them from southern Gaul (507). His conversion to Catholicism resulted in a great many of his people converting to Catholicism as well.[10] According to legend, it was only by invoking the God of his Christian wife, Clotilde, that he defeated his enemy. Clotilde was almost certainly instrumental in Clovis' conversion to the Catholic faith.