Cosimo Concini (1570, Florence – 1604, Valladolid) was an Italian diplomat serving Grand Duchy of Tuscany in 16th-century.
[1] He had a successful ecclesiastical and diplomatic career, largely due to the influence of his father and grandfather, Bartolomeo Concini, both of whom had served as First Secretary to the Grand Dukes Cosimo I, Francesco I, and Ferdinando I of Tuscany.
Concini's diplomatic career took off on 17 November 1595, when he was named the Grand Duke's resident ambassador to the imperial court.
This appointment was largely due to his father Giovan Battista's continued influence at the Medici court.
Soon after arriving in Spain, Concini fell ill. His letters from 1603 reveal growing financial troubles, made worse by his declining health.