Analysis of information sources in references of the Wikipedia article "Processo de Galileu Galilei" in Portuguese language version.
Inside the Catholic domain, the first difficulties worth mentioning begin to arise when, toward the end of 1610 or the beginning of 1611, appears the manuscript of an essary written by Lodovico (or Ludovico) delle Colombe Contro il moto della terra. The author is a fierce Aristotelian attacking almost everything coming from Galileo, himself known to be very critical of Aristotelians of his age and having criticized a book of delle Colombe in 1604 (Drake 1980, 50; Blackwell 1991, 59–61).
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Thus the whole "Galileo affair" starts as a conflict initiated by a secular Aristotelian philosopher, who, unable to silence Galileo by philosophical arguments, uses religion to achieve his aim.
Galileo did not simply reject the Aristotelian model of the universe: he offered concrete evidence that it was wrong. In 1609 and 1610 his use of a telescope for astronomical observation—the first in history—revealed spots on the sun and mountains on the moon that undermined the Aristotelian belief in celestial perfection ... Galileo made enemies with ease—a result of his quick wit, sharp tongue, and distrust of authority. Many of them were priests, as well as astronomers and mathematicians, and found reason to dislike Galileo in both capacities.
Finally, another lesson in a different direction, but one not often drawn, is that it was Galileo, who believed in the Bible, who was advancing a better scientific understanding of the universe, not only, as we have seen, against the obscurantism of some churchmen, but (and first of all) against the resistance (and obscurantism) of secular philosophers of his time who, like the churchmen, were also convinced disciples of Aristotle.
Inside the Catholic domain, the first difficulties worth mentioning begin to arise when, toward the end of 1610 or the beginning of 1611, appears the manuscript of an essary written by Lodovico (or Ludovico) delle Colombe Contro il moto della terra. The author is a fierce Aristotelian attacking almost everything coming from Galileo, himself known to be very critical of Aristotelians of his age and having criticized a book of delle Colombe in 1604 (Drake 1980, 50; Blackwell 1991, 59–61).
...
Thus the whole "Galileo affair" starts as a conflict initiated by a secular Aristotelian philosopher, who, unable to silence Galileo by philosophical arguments, uses religion to achieve his aim.