In a note and sketch dating back to approximately 1515, da Vinci references some of the ideals and machines Brunelleschi invented back when he was constructing the duomo. The sketch and note related to some of da Vinci's work on designing parabolic mirrors and he says, "Remember the solders used for soldering the ball on Santa Maria del Fiore (Florence Duomo)." This artifact exemplifies the inspiration Leonardo drew from Brunelleschi and his machines and further proves Leonardo's involvement with the construction of the duomo.

Source: Leonardo da Vinci in Florence: On the Lantern. (n.d.). Retrieved from https://erenow.net/biographies/leonardo-da-vinci-the-flights-of-the-mind...