[2] Some historians, however, speculate that the motives behind Caccini's sermons were questionable because "his fanaticism was never divorced from personal ambition for advancement within the Dominican order.
In fact, Caccini's highly controversial sermons, which often vilified critics of Church doctrine, eventually resulted in discipline by the Archbishop of Bologna.
Another famous member of the Pigeon League was Niccolò Lorini, who often utilized references to Scripture in his fiercely critical sermons against Galileo.
On December 20, 1614, Caccini issued a sermon at the Santa Maria Novella in Florence strongly opposing Galileo's support of Copernican theory.
[2] While the exact text of the sermon is not clear, historians suggest that Caccini preached that mathematics and science were contrary to the word of the Bible, and therefore, heretical.
[7] Caccini attempted to play on the words of the passage by starkly contrasting Galileo's allegedly heretical acts to the unwavering faith of the inhabitants of Galilee.
[9] By the time the Holy Office called Caccini to testify against Galileo, he was residing at the Roman convent of Santa Maria sopra Minerva.
Caccini stated that following his sermon, he reported to the Father Inquisitor in Florence that Galileo's supporters should be disciplined for their "petulant minds.
"[11] Caccini accused Galileo's followers of making blasphemous statements that questioned God's existence and the Church's declaration that miracles were acts performed by saints.
Gradually his career progressed in Rome, and he eventually became the prior of the monastery of San Marco where he continued to assist in the prosecution of Galileo.