"Julius Porcellis, son of the marine painter Jan Porcellis, was probably born around 1610 in Rotterdam. His first documentary mention can be found in his father's will of 1631, from which it can be concluded that he was already of age at the time. Until his death in Leiden in 1632, Jan Porcellis had moved several times with his family; stays in Antwerp, Haarlem, Amsterdam and in Voorburg near the Hague are documented. Julius's inheritance included not only the sum of 400 guilders, but also the remaining paintings that were still in the workshop. Around 1635 he moved to Rotterdam, where he was documented in 1644, and a few years later to Leiden, where he died in September 1654.
Julius Porcellis probably received his artistic education from his father, whose style and monogram he adopted. Houbraken already reported that it was difficult to separate the two. Furthermore, his works are often confused with those of the Antwerp painter Jan Peeters due to the identical monogram."