I believe the correct answer is Cimabue.
Cimabue (also known as Cenni di Pepo/Cenni di Pepi) was an Italian painter and designer of mosaics from Florence who is considered a transitional figure from the traditional Byzantine style of art, as he was the first to of Italian painters to break from Italo-Byzantine style. His new technique included depicting figures with more-advanced lifelike proportions and more shading than in Italo-Byzantine style.