Reports the study of the wooden structure of Brunelleschi's cupola. From an analysis of the position and form of the wooden chain in the dome of Santa Maria del Fiore in Florence, Italy, the author draws conclusions as to the structural logic of the dome itself. The history of this wooden architectural device is tied to the many difficulties Brunelleschi had to overcome during construction, among which was his dispute with Giovanni di Gherardo da Prato. The author suggests that the so-called chain of chestnuts can be used to strengthen the dome.