Passage: Religious beliefs in the Eastern Empire and Iran were in flux during the late sixth and early seventh centuries. Judaism was an active proselytising faith, and at least one Arab political leader converted to it. Christianity had active missions competing with the Persians' Zoroastrianism in seeking converts, especially among residents of the Arabian Peninsula. All these strands came together with the emergence of Islam in Arabia during the lifetime of Muhammad (d. 632). After his death, Islamic forces conquered much of the Eastern Empire and Persia, starting with Syria in 634–635 and reaching Egypt in 640–641, Persia between 637 and 642, North Africa in the later seventh century, and the Iberian Peninsula in 711. By 714, Islamic forces controlled much of the peninsula in a region they called Al-Andalus.The Islamic conquests reached their peak in the mid-eighth century. The defeat of Muslim forces at the Battle of Tours in 732 led to the reconquest of southern France by the Franks, but the main reason for the halt of Islamic growth in Europe was the overthrow of the Umayyad Caliphate and its replacement by the Abbasid Caliphate. The Abbasids moved their capital to Baghdad and were more concerned with the Middle East than Europe, losing control of sections of the Muslim lands. Umayyad descendants took over the Iberian Peninsula, the Aghlabids controlled North Africa, and the Tulunids became rulers of Egypt. By the middle of the 8th century, new trading patterns were emerging in the Mediterranean; trade between the Franks and the Arabs replaced the old Roman economy. Franks traded timber, furs, swords and slaves in return for silks and other fabrics, spices, and precious metals from the Arabs.

Question: Where did the Abbasids move the capital to?
Baghdad