There was a late holdover of Arianism in Christianity. The Visigothic Arians had developed certain liturgical peculiarities, along with the theological heresies. When they converted to true Christianity a compromise was made for their liturgical ideas, which became the Gothic Rite of the Church. Many true Christians who had been persecuted by the Arians objected to this and would not accept the Gothic Rite.
Most Christians felt that this liturgical concession was a small price to pay to finally destroy the vile Arian heresy. After Spain was conquered by the Moslems at the end of the 7th century, it lacked the strength to maintain the seperate Gothic Rite, which eventually disappeared, which is why Spanish Christianity was essentially identical with the rest of Western Christianity.
And the adversary has been striving vigorously to destroy the flock ever since. Islam and Arianism were intended to displace genine Christian faith by offering or forcing acceptance of a counterfeit faith--one that would acknowldge the form of Jesus Christ while steadfastly denying the power. Because that power was made fully manifest in the resurrection, the resurrection had to be denied and denounced as vigorously and thoroughly as possible. Islamic rejection of the crucifixion and resurrection goes beyond ordinary rejection--it is a pathological rejection. And that pathology betrays the true nature and identity of the spirit that inspires it.