Two factors played a crucial role in the dome's construction: efficient worksite organization, and the availability of machines capable of moving and lifting massive weights to great heights.
Brunelleschi left no drawings or verbal descriptions of the machines he designed and used. However, the highly innovative features of his machines attracted the attention of the leading engineers of the fifteenth century - Taccola, Francesco di Giorgio, Bonaccorso Ghiberti, and Giuliano da Sangallo - who recorded them extensively in their drawings.
One of these engineers was the very young Leonardo da Vinci, who, upon his arrival in Florence in 1469, was apprenticed to Verrocchio's workshop. At the time, the latter was engaged in placing the heavy copper sphere atop the lantern at nearly 100 meters above the ground. Leonardo's notebooks contain very detailed sketches of the main machines used by Brunelleschi for the construction of the dome.