Hermanus Willem Koekkoek, son of Willem, followed in the footsteps of his uncle Hermanus jr in 1901 and left Amsterdam for a long stay in London. He had been there before, from 1887 to 1891, and now he would live there for about twenty years. In England he became known for his drawings of the Boer War (1899-1902) and as a draftsman at the royal court. He found work as an illustrator for magazines such as 'Illustrated London News', 'The Sketch' and 'The Royal Magazine' in the British capital. During the First World War in particular, military performances by his hand appeared regularly in the first magazine. In London, and after returning to the Netherlands, he worked for 'Williams & Sutch'. The United Arts Gallery, who also sold his paintings in the United States and Canada. Correspondence with this art dealer shows that Hermanus Willem's choice of subject was more varied than is currently proposed. Military scenes are now seen as his main subject, but it turns out that he also painted impressionistic landscapes, cityscapes and even a single still life. Exhibition lists for his Dutch art dealers, including Oldenzeel in Rotterdam and Th. Flax in Amsterdam, exhibit the same, surprising image of a versatile artist.