Antonio Squarcialupi (c. 1416–1480) was an influential Italian composer and organist of the early Renaissance period, primarily associated with the genre of sacred music. He was born in Florence and served as the organist at the Santa Maria del Fiore cathedral, where his work contributed significantly to the development of polyphonic music. Notable works include a collection of sacred motets and settings of the Mass, which reflect the emerging style of early polyphony. Squarcialupi's compositions are characterized by their intricate counterpoint and use of rich harmonies, which were innovative for his time. His music often incorporated the use of multiple voices, which became a hallmark of Renaissance music. Squarcialupi is also recognized for his connection to the Squarcialupi Codex, a significant manuscript containing a wealth of Italian secular music from the early Renaissance, although much of the music is attributed to other composers. His influence on the evolution of polyphonic style laid the groundwork for later composers, including Josquin des Prez and Giovanni Pierluigi da Palestrina, marking him as a pivotal figure in the transition from medieval to Renaissance music.