The period of extraordinary intellectual, scientific, and cultural achievement in the Islamic world from the Abbasid caliphate through the 13th century — during which Baghdad was the world's intellectual capital, scholars preserved and extended Greek learning, and Muslim scientists made foundational contributions to mathematics, astronomy, medicine, and optics that were essential to the European Renaissance.
While Europe was in the early medieval period, the Islamic world was running the world's most sophisticated hospitals, libraries, and observatories. The algebra we use came from Baghdad. The astronomical tables used by Columbus were Islamic. The word 'algorithm' comes from a 9th-century Baghdad mathematician. The European Renaissance did not emerge from nowhere.