The Amsterdammer Ko Cossaar started his artistic career as a painter of stage décors and also followed evening classes at the Rijksacademie. After receiving two grants from the Willink van Collenfonds in 1901, he lived for a longer period in Paris and London. In Paris he became friends with Kees van Dongen, in London Matthijs Maris introduced him to the art dealer Goupil, where he also exhibited. In 1909 he settled in The Hague. Cossaar drew, watercolored and painted mainly cityscapes and church interiors, but in the period 1928-1933 was also inspired by literary themes. Cossaar was a member of Arti et Amicitiae in Amsterdam and of the Haagse Kunstkring, the Hollandsche Teeken-Maatschappij and Pulchri Studio in The Hague.