According to Houbraken, he was the son of Pieter Jansz Schagen, an important councilman of Alkmaar, who was taught to paint first by Salomon van Ravesteyn and then by the horse painter Pieter Cornelisz Verbeeck.
[1] Schagen painted a portrait of the King of Poland to "prove his mastership of the art" for him.
[1] From there he went home for a short stay before travelling by boat to Dieppe and onwards to Paris, where he painted portraits of many important people there and in Orleans.
[1] He visited admiral Maarten Tromp there, who invited him to draw his ships and observe the sea battle for inspiration.
[1] After observing the battle however, Schagen decided to return to the Netherlands without drawing the ships.