After decades of war, Milan and Lombardy became part of the Spanish empire in the second half of the sixteenth century. Two great archbishops of the Counter-Reformation, Carlo and Federigo Borromeo, are Milanese symbols of that period. With the advent of peace, the building of churches and mansions resumed.
Around 1550, young Leonardo Spinola arrived in Milan from Genoa and started work with a Genoese banker, Tommaso Marino. He eventually married his niece, won his trust, and became rich. In the pursuit of his grand plan to build what would become Palazzo Spinola, he purchased land and buildings in the San Paolo district of Milan. In 1562, he bought a house that became his family’s home, then in 1582 he bought the Porro house, an adjacent property, and added a garden.
Probably due to Spinola’s financial difficulties, the construction was not completed until 1597; the date is still visible under the cornice of the mansion.
After Leonardo’s death, the mansion changed hands several times. First it passed to the Marino family; in 1643, it went to Don Domenico Odescalchi; in 1646, it became the property of Abbot Giacinto Airoldi. Finally it went to the Cusani family, from whom the palazzo was officially purchased by Società del Giardino on 9 February 1819. It had already become the home of the Società del Giardino on 29 September 1818, and has remained so ever since.
The year 1820 marked the inauguration of the splendid neo-classical grand salon (called ‘The Golden Hall’), which would be the scene of countless prestigious events. Additions and transformations followed in the nineteenth and twentieth centuries.
After the severe damage caused by the bombings of August 1943, the reconstruction of the damaged areas was completed in 1947 under the architect Cassi Ramelli.