Francesco Talenti (c. 1300-1370) was the chief architect of Florence cathedral and campanile after Arnolfo di Cambio, Giotto and Andrea Pisano; some give him credit for making sure it was, in its day, the largest church in the world. He also worked on Orsanmichele.
His son Simone made the beautiful windows for the same and is often credited with building or helping to build the Loggia dei Lanzi.
Image by Carlo Raso