Towards 1445 Cosimo de’ Medici, known as Cosimo il Vecchio, launched the construction of his own residence on Via Larga, on the corner with Via de’ Gori.
He entrusted the commission for the work to the architect Michelozzo di Bartolomeo. According to the sources, Cosimo had previously rejected a design presented by Filippo Brunelleschi “because it was too lavish and magnificent” and would “arouse envy among the citizens, rather than being a grand ornament for the city, and comfortable in itself” (G. Vasari, 1568).

Completed about ten years later, the Palazzo Medici designed by Michelozzo appeared as a completely new style of building within the Florentine urban panorama, capable of combining tradition (pietra forte, or fine grained sandstone, and rustication) with the new Renaissance concepts.
In comparison to the present building, extended in the seventeenth century, the palazzo of Cosimo il Vecchio had the appearance of a cube, at once austere and elegant, presenting a corner view to those arriving from the Duomo. The facade on Via Larga was made up of ten bays, with another nine on the Via de’ Gori side.