Contemporaries have noted that Borromini's architecture features a unique apparatus of individual forms for each building, which supposedly detaches him from the models of antiquity and the Renaissance. This study examines exemplary buildings by Borromini, particularly from his early creative phase, and offers new insights into the architect's design intentions and methods, his relationship to antiquity, influences from models such as Michelangelo, and architectural theory, through in-depth analyses of his hand drawings.