In February 1548 Cosimo I sent him to Venice, but it was he who prepared the plot against Lorenzino de' Medici, who oddly enough, the very same month, was hit by two killers from Volterra.
In 1552 he obtained from Pope Marcellus II an appointment as canon of Abbey Hill of Piedmont.
In 1555 he entered the papal court, opposing the election of Pope Paul IV, who suffered much.
In 1559 he was at the service of Giovanni Angelo de'Medici as a secretary, who became Pope Pius IV and appointed Lottini Bishop of Conversano in 1560.
Before his death (in Rome, in August 1572) Lottini gave his brother a treatise of considerations and personal notes on different themes, from the military to the care of physical life.