Complex sentence: Between 1430-35, Alberti cast a bronze, self-portrait plaque in a style that was clearly influenced by Roman imperial portraits and was the first labeled self-portrait of an artist.
Split into simpler sentences: Between 1430-35, Alberti cast a bronze, self-portrait plaque in a style that was clearly influenced by Roman imperial portraits. Alberti's plaque was the first labeled self-portrait of an artist.