Complex sentence: Among his first important clients was the connoisseur and collector Johann Matthias von der Schulenburg, for whom Guardi produced copies after the work of other artists, as well as a series of Turkish-inspired interiors as easel pictures for private decoration.
Split into simpler sentences: Among his first important clients was the connoisseur and collector Johann Matthias von der Schulenburg, for whom Guardi multiple paintings with an Orientalist theme. He produced copies after the work of other artists, as well as a series of originals with Turkish-inspired interiors as easel pictures for private decoration.