Hasius, between Rembrandt and Jan Steen
Three famous 17th century dutch painters, Jan van Goyen, Jan Steen and Rembrandt (van Rijn) were related.
Jan Steen's father-in-law was Jan van Goyen, so that relation is easy to establish.
Both men were related to the most famous dutch painter, Rembrandt, by the influential Hasius family. Rembrandt's aunt married Willem Hendriks Hasius. Jan Steen's uncle married Annetge Symonsdr Hasius. Willem was Annetge's uncle.
In another way: Symon Heyndriks Hasius was Rembrandt's uncle's brother, while at the same time he was the father of Jan Steen's aunt.
Genealogical sources: (CBG)