BETWEEN 1605 and 1609 Monsignor Giovanni Battista Agucchi was involved in planning three commemorative monuments. Only two of them were constructed: the tomb of his brother, Cardinal Girolamo Agucchi in S. Pietro in Vincoli, Rome (1605–06) and the memorial to the same cardinal in S. Giacomo Maggiore, Bologna (1608–09). These were both designed by Domenichino, and affirm the artist's close ties to Agucchi with whom he shared an interest in architecture and ornament all'antica. The third, which has remained unknown until now, was a project initiated in 1608, shortly before Agucchi turned his attention to his brother's tomb in S. Giacomo Maggiore. It was never realised, but a group of drawings and letters recently discovered in the Vatican Library document the patron's intentions, showing that Agucchi had decided to embellish the modest memorial to Cardinal Filippo Sega that his brother had earlier erected in the presbytery of Piacenza Cathedral. The artist whom he asked to help with the designs was Lodovico Carracci.

THE manuscript of Borromini's Opus Architectonicum, drafted in 1647, begins with a handsome dedication to the 'Mar- chese di Castel Rodriguez', whom the architect had had occasion to know 'nel tempo chefui honorato di servirla in questa Citta nel disegno della regiafabrica cominciata da suoi antenati, e dei sepolchri de suoi heroi'.' Yet no trace is left in Rome of any such chapel or ancestral seat. Who was this man, who looms so large in Borromini's life and whose attentions moved the usually silent architect to say, che mi amava piz da figlio, che da servo?