It was built by Brunelleschi
he built the cathedral of Florence
Filippo Brunelleschi, an Italian architect, designed and built the dome of Florence Cathedral. Completed in 1434, it is considered a masterpiece of Renaissance architecture and engineering.
Arnolfo di Cambio and Filippo Brunelleschi were the two architects that built the Florence Cathedral.
Filippo Brunelleschi
It was Brunelleschi. He built the dome of the Basilica di Santa Maria del Fiore, Florence's cathedral.
The Dome!
The dome in the Cathedral of Florence was designed by Arnolfo di Cambio. It was engineered by Filippo Brunelleschi and completed in 1436.
The Cathedral of Florence
It is 114 metres tall.
You might be thinking of the Pantheon, however the Pantheon was more hemispherical and would not have worked on the scale of Brunelleschi's dome so he had to use newer Gothic methods.
Filippo Brunelleschi