Complex sentence: Niccolo di Ser Sozzo (documented as active 1334--1363), an Italian painter and manucript illuminator, generally has been identified as Niccolo di Ser Sozzo di Francesco Tegliacci, but recent research points instead to a Niccolo di Ser Sozzo di Stefano.
Split into simpler sentences: Niccolo di Ser Sozzo (documented as active 1334--1363) was an Italian painter and manuscript illuminator. He generally has been identified as Niccolo di Ser Sozzo di Francesco Tegliacci, but recent research points instead to a Niccolo di Ser Sozzo di Stefano.