Cosimo II de' Medici, Grand Duke of Tuscany

Cosimo II de' Medici was born in May 1590, the elder son of Ferdinando I de' Medici and Christina of Lorraine. He became Grand Duke of Tuscany in 1609, at nineteen. Over the twelve years that followed, he let ministers run the machinery of state while he concerned himself with other matters. Chief among them: Galileo Galilei, who had taught him as a boy and whom Cosimo made his court mathematician and philosopher. That patronage gave Galileo shelter and funding during the years he peered through telescopes and articulated what he saw. Cosimo died in February 1621, at thirty, his reign a footnote except for the man he kept working.