Complex sentence: By this time, Melli is considered one of the major representatives of the "Scuola Romana" and in 1950 is finally invited at the Biennale di Venezia, which will honour him with a "personale".
Split into simpler sentences: By this time, Melli was considered one of the major representatives of the "Scuola Romana". In 1950, he was finally invited to exhibit at the Biennale di Venezia, which honoured him with a "personale".