On 27 March 1106, Alfonso VI confirmed a donation to the monastery of Lorenzana: "(...) ", an unusual formula that confirms a legitimate marriage. Salazar y Acha and Reilly interpret this quote as proof that the king had married Zaida, thus legitimizing their son and the relationship of concubinage. Gambra, however, disagrees and says that it is "an extremely weak argument, starting with the documentary reference, which is scarcely significant. Its character is rather ornamental and literary". Montaner Frutos also says that this hypothesis is "unlikely and problematic" since it was not necessary for the king to marry Zaida to legitimize his son and that, furthermore, the French Isabel died in 1107 according to her epitaph. Montaner Frutos also mentions a donation from Queen Urraca years later, in 1115, when she donated properties to Toledo Cathedral and only mentions one Isabel as the king's wife.