Alexander Kronemer writes:

At its peak, it lit the Dark Ages with science and philosophy, poetry, art, and architecture. It was the period remembered as a golden age for European Jews. Breakthroughs in medicine, the introduction of the number zero, the lost philosophy of Aristotle, even the prototype for the guitar all came to Europe through Islamic Spain.

However, his conclusion has the right heart though not the best of analyses:

At its best, the history of Islamic Spain is a model for interfaith cooperation that inspires those who seek an easier relationship among the three Abrahamic faiths. At its worst, it’s a warning of what can occur when political and religious leaders divide the world. It reminds us what really happens when civilizations clash.