The publication of this work was of especial significance, because it was the first in which Galileo decidedly takes the side of the Copernican system. This accounts for the extraordinary sensation made by these essays. The controversy on the two systems came more and more to the front. And yet, notwithstanding all this, no theological scruples seem at first to have been felt at Rome, even in the highest ecclesiastical circles. On the contrary, we find the cardinals Maffeo Barberini[86] (afterwards Pope Urban VIII.), and Federigo Borromeo,[87] thanking Galileo in the most friendly terms for sending them his work, and expressing their sincere admiration for the researches described in it. And Battista Agucchia, then one of the first officials at the court of Rome, and afterwards secretary of Pope Gregory XV., in a similar letter of thanks,[88] not only fully endorsed these opinions, but expressed his firm belief that they would in time be universally acknowledged, although now they had many opponents, partly from their novelty and remarkable character, and partly from the envy and obstinacy of those who had from the first maintained the contrary view. The scientific circles of the university town of Pisa were far less friendly to the Copernican ideas than the higher ecclesiastics at the papal residence. Father Castelli, who in October of the same year was called to the chair of mathematics at this university, reports in a letter of 6th November,[89] in which he tells Galileo what reception he had met with from the heads of the college, that the proveditor of the university, Mgr. d’Elci, had expressly forbidden him at his first interview to treat in his lectures of the double motion of the earth, or even to take occasion in any digression to mention it as probable!