Complex sentence: Cantor's belief in infinite sets that were accessible to mathematicians was criticized by some Christian theologians who thought that his theory supported pantheism, which was considered a heresy by the Catholic Church.
Split into simpler sentences: Cantor's belief in infinite sets that were accessible to mathematicians was viewed with suspicion by some Christian theologians. In fact, they thought that his theory supported pantheism, which was considered a heresy by the Catholic Church.