How did Francesco Borromini criticize Gian Lorenzo Bernini after the St. Peter’s tower project failed?

After the failure of the St. Peter’s tower project, Francesco Borromini emerged as the most effective and destructive critic of Gian Lorenzo Bernini. Following the 1645 decision to remove the bell towers that Bernini had attempted to complete—which had suffered from technical deficiencies—Borromini publicly accused Bernini of incompetence.1

This conflict was part of a long-standing professional and personal rivalry. Borromini, who had worked under Bernini at St. Peter’s, felt deeply resentful that his own contributions had gone unrewarded and unrecognized by his colleague. Their antagonism was further fueled by their disparate personalities and approaches to architecture; while Bernini was a socially adept and successful figure, Borromini was a withdrawn, melancholic, and highly specialized architect who prided himself on his technical training.1