Sims was an accomplished and successful academic painter in oil, tempera and watercolour, of figure subjects, genre scenes and landscapes. He studied in London and Paris and exhibited at the Royal Academy from 1894. He won Gold Medals at the Amsterdam and Pittsburgh International Exhibitions in 1912, was elected RWS in 1914 and RA in 1916. He was an official war artist in 1918 and Keeper of the Royal Academy Schools from 1920-26. In the early 1920's Sims began to show signs of mental illness, possibly schizophrenia and his pictures became more improvisatory in execution and revelatory in content.
These works, of which The Prayer is an example, seem suffused with a sense of the numinous; his figures emanate a spectral light and are contained within glowing auras. His new mystical paintings were shunned by those who had once feted and revered him. Increasingly depressed, he went out at dawn on 13 April 1928 and shot himself at his home in St. Boswells, Scotland. Sims is considered to be a prime example of the 'trained' artist whose style changed because of psychiatric illness. which is why he is represented in the Bethlem Royal Museum and Archive in Beckenham. Kent.