In addition to shipbuilding, Dudley was busy with many projects in Tuscany, including the Livorno's breakwater and harbour fortifications, draining local swamps, and building a palace in the heart of Florence. He also designed new galleys, and he wrote his memoirs of navigation and seamanship between 1610 and 1620. Later, Dudley incorporated his notes into six volumes of "Dell'Arcano del Mare" ("The Secret of the Sea"), self-published in 1646–1647. He also wrote a "Maritime Directory" as a manual for the Tuscan Navy but it was never published. In 1631, his wife Elizabeth died the day after giving birth to her last child. Several of their 13 children married into the Italian nobility. In 1644, King Charles I created Dudley's second wife Alice Duchess of Dudley for life and recognized Dudley's legitimacy but did not restore his titles and estate. Robert Dudley died on 6 September 1649 outside Florence in Villa Rinieri (now Villa Corsini a Castello). He was buried at San Pancrazio in Florence.