284 A BRIEF SURVEY OF HUMAN HISTORY to a greater equality of classes, the growth of a free peasantry and of guilds of artisans, and the development of trade and industry. In the field of politics they were followed by the rise of the system of Estates, by a growing centralization of government, and by the appearance of written law and a regular judicial administration. In the great world of culture, philo- sophy developed its greatest thinkers after the Crusades and the connexion with the Arabs which they brought : even mysticism assumed a scientific character : the study of the ancient lang- uages grew in extent and fertility : historiography and geogra- phy acquired a new vigour: a vernacular poetry arose-: Gothic architecture succeeded: a Romanesque, and a1 finer taste appeared in sculpture and painting.'1 1. The Legacy of Islam, p. 51.