The High Middle Ages produced many different forms of intellectual, spiritual and artistic works. The age also saw the rise of ethnocentrism, which evolved later into modern national identities in most of Europe, the ascent of the great Italian city-states and the rise and fall of the Islamic civilization of Al-Andalus. The rediscovery of the works of Aristotle, at first indirectly through Medieval Jewish and Islamic Philosophy, led Maimonides, Avicenna, Averroes, Thomas Aquinas and other thinkers of the period to expand Scholasticism, a combination of Judeo-Islamic and Catholic ideologies with the ancient philosophy. For much of this period, Constantinople remained Europe's most populous city, and Byzantine art reached a peak in the 12th century. In architecture, many of the most notable Gothic cathedrals were built or completed around this period.