 Called to Spain in 1529 by Charles V, Holy Roman Emperor, he was appointed "Court Clock Master" and built the "Cristalino", an astronomical clock that made him famous in his time.Philip II of Spain named him "Matemático Mayor".He worked and lived in Toledo, where he built the "Artificio de Juanelo", an engine that, driven by the river itself, lifted water from the Tagus to a height of almost 100 meters, to supply the city and its castle (Alcázar).