Walter Bertram Potter (1872-1918), known as Bertram, was the younger brother of the children's author and illustrator Beatrix Potter. As a child he shared his sister's passions for drawing and natural history and during the family's long summer holidays in the countryside he would accompany Beatrix on expeditions to study and sketch plants and animals. Between 1885 and 1907 the Potter family spent nine summers at Lingholm, a stately home built in the 1870s on the north-west side of Derwentwater.

It was Bertram who first encouraged Beatrix to publish some early rabbit drawings as greetings cards in 1890 and she continued to seek his advice when illustrating the Peter Rabbit books: 'My brother is sarcastic about the figures; what you & he take for Mr. McGregor's nose, was intended for his ear, not his nose at all' (Letter to Norman Warne, 2 May 1902). Although overshadowed by the success of his sister, Bertram became an artist in his own right. He produced much larger scale oil paintings and etchings and exhibited work at the Royal Academy.