Isaac was the third son of Adam Willaerts (1577-1664), the leading Dutch marine painter in Utrecht during the first half of the 17th Century, who was also his master. As his father and brother, he specialized in maritime and coastal views. He became the dean of the Guild of St. Luke in Utrecht in 1666, two years after the death of his father who had, in turn, founded the Guild in that city in 1611.
Isaac Willaerts was strongly influenced by his father in compositional techniques although he was characterised by broader brushstrokes akin to those of his elder brother Abraham. The precise colorful detail in the foreground and the horizontal coastal format in the present painting are characteristic of such compositions.
Ships and figures always occupy an important place in the oeuvre of Isaac Willaerts, as is also the case in this painting. Close to the shore a galley is carrying on top of the stern the Triregnum, the Papal Tiara formed by the three crowns symbolizing the triple power of the pope. On the flag we see the letters SPQR: the Senate and the People of Rome, so it is indicating we are dealing with a Papal galley. On the right of the galley there is a Dutch tree-master, the ‘Amsterdam’. It flying its pennant on the main, indicating a commander of a squadron is on board. On the waterside strangers greet each other, merchants are busy in conversation and folk men are passing casually. In the design of the fortification Willaerts let his imagination roam freely.
Through a sophisticated coherence of the visual elements an entertaining and lively presentation has arisen. From the fact that a second painting from Willaerts is known (formerly collection Rob Kattenburg) we can deduce the subject and the composition were appreciated by his contemporaries. Paintings by Isaac Willaerts are to be found in various renowned museum collections in Amsterdam, Emden, Rotterdam, Stockholm and Utrecht amongst others.