This is not my field, but I have taken graduate-level courses on Andalusian history and the history of mathematics.
From what I can tell, the claim is at best imprecise and at worst an outright misrepresentation of history. For example, in an article published by the British Society for the History of Science, "From Abacus to Algorism: Theory and Practice in Medieval Arithmetic," Gillian Evans writes that:
The treatises on the abacus that seem to have proliferated in the late eleventh and early twelfth centuries comprise more or less extended preliminaries on the nature of number and the usefulness of knowing how to calculate upon the abacus. They usually give the Arabic numerals and their names, along with the names and symbols for the Roman duodecimal fractions, but they prefer, for the most part, to use Roman figures for the integers in their worked examples and in their multiplication tables. They confine themselves, typically, to multiplication, division and fractions, and, strictly, to the mechanics of the abacus.
In the "Arithmetic of the Medieval Universities," an article published by the National Council of Teachers of Mathematics, Dorothy V. Schrader writes:
The outstanding mathematical genius of the period was Gerbert, who taught the quadrivium with marked success in the cathedral school at Rheims from 972 to 982. Gerbert improved the
abacus by placing symbols at the top of each column, and so extended its use. He
developed a method of division, making possible all four fundamental operations
on the abacus.
The sources I quote here suggest that even before the widespread introduction of Arabic numerals in Christian Europe, division was widely known, routinely performed on the abacus (and using hands), attested to in the literature of the period, and taught in the universities--all well before the 13th century.
Additionally, for even more examples of the above consult the freely-available Rara Arithmetica.
