In 1239 Gregory IX resumed his struggle with Frederick, excommunicated him for a second time, and renewed that warfare of public abuse in which the papacy had already suffered severely. The controversy was revived after Gregory IX was dead, when Innocent IV was Pope; and again a devastating letter, which men were bound to remember, was written by Frederick against the church. He denounced the pride and irreligion of the clergy, and ascribed all the corruptions of the time to their pride and wealth. He proposed to his fellow princes a general confiscation of church property—for the good of the church. It was a suggestion that never afterwards left the imagination of the European princes.
We will not go on to tell of his last years. The particular events of his life are far less significant than its general atmosphere. It is possible to piece together something of his court life in Sicily. He was luxurious in his way of living, and fond of beautiful things. He is described as licentious. But it is clear that he was a man of very effectual curiosity and inquiry. He gathered Jewish and Moslem as well as Christian philosophers at his court, and he did much to irrigate the Italian mind with Saracenic influences. Through him the Arabic numerals and algebra were introduced to Christian students, and among other philosophers at his court was Michael Scott, who translated portions of Aristotle and the commentaries thereon of the great Arab philosopher Averroes (of Cordoba). In 1224 Frederick founded the University of Naples, and he enlarged and enriched the great medical school at Salerno University. He also founded a zoological garden. He left a book on hawking, which shows him to have been an acute observer of the habits of birds, and he was one of the first Italians to write Italian verse. Italian poetry was indeed born at his court. He has been called by an able writer, “the first of the moderns,” and the phrase expresses aptly the unprejudiced detachment of his intellectual side.
A still more striking intimation of the decay of the living and sustaining forces of the papacy appeared when presently the Popes came into