Francesco Castello was born on 25 September 1599 in Bissone in the district of Lugano. Many members of his family were stonemasons, so at the age of 9 (or 15) he moved to Milan to become an apprentice. In 1621 he left for Rome where he assumed his mother’s last name, Borromini. Initially he earned a living as a sculptor next to his uncle, Leone Garovo, but he soon moved to the architectural shop of Carlo Maderno, another of his relatives. Borromini spent all his time drawing and was gradually entrusted with more responsibility.