This study, drawing on new information from unpublished documents, reconsiders the working methods and responsibilities of sculptor and architect Bartolomeo Ammannati in the context of Cosimo I de’ Medici’s creation of a grand ducal Tuscan empire. Ammannati was an indispensable part of the broader enterprise of ducal and grand ducal building activity, urban development, and court bureaucracy. His success was reliant on skills different than those emphasized by Giorgio Vasari. Instead of divinely inspired disegno or rampant terribilità, Ammannati showed his technical, organizational, and supervisory skills to move stones, build bridges, manage waterways, and keep track of expenses— the very stuff behind Cosimo’s empire building. Specific projects include many that are well known; others are entirely new to scholars. This essay emphasizes the importance of labor management, transportation networks, account keeping, engineering, and water management as aspects vital to civic governing and empire building in this dynamic though unstable phase of the early modern period.