Complex sentence: Anton Boys' role as a court painter appears to have been to paint portraits of historical and living members and their consorts of the imperial family, which are in the collection of the Kunsthistorisches Museum in Vienna.
Split into simpler sentences: Anton Boys' role as a court painter appears to have been to paint portraits of historical and living members of the imperial family and their consorts. These portraits are now in the collection of the Kunsthistorisches Museum in Vienna.