disturbance from 1785 and was admitted to St Luke's Hospital for Lunatics in Old Street in 1799. She was moved in 1800 to Bethlem Hospital, a mental asylum, where she died in 1804. Turner was sent to his maternal uncle, Joseph Mallord William Marshall, a butcher in Brentford, then a small town on the banks of the River Thames west of London, where Turner attended school. The earliest known artistic exercise by Turner is from this period—a series of simple colourings of engraved plates from Henry Boswell's Picturesque View of the Antiquities of England and Wales. Around 1786, Turner was sent to Margate on the north-east Kent coast. There he produced a series of drawings of the town and surrounding area that foreshadowed his later work. By this time, Turner's drawings were being exhibited in his father's shop window and sold for a few shillings. His father boasted to the artist Thomas Stothard that: "My son, sir, is going to be a painter". In 1789, Turner again stayed with his uncle who had retired to Sunningwell (now part of Oxfordshire). A whole sketchbook of work from this time in Berkshire survives as well as a watercolour of Oxford. The use of pencil sketches on location, as the foundation for later finished paintings, formed the basis of Turner's essential working style for his whole career. Many early sketches by Turner were architectural studies or exercises in perspective, and it is known that, as a young man, he worked for several architects including Thomas Hardwick, James Wyatt and Joseph Bonomi the Elder. By the end of 1789, he had also begun to study under the topographical draughtsman Thomas Malton, who specialised in London views. Turner learned from him the basic tricks of the trade, copying and colouring outline prints of British castles and abbeys. He would later call Malton "My real master". Topography was a thriving industry by which a young artist could pay for his studies. Career Turner entered the Royal Academy of Art in 1789, aged 14, and was accepted into the academy a year later by Sir Joshua Reynolds. He showed an early interest in architecture, but was advised by Hardwick to focus on painting. His first watercolour, A View of the Archbishop's Palace, Lambeth was accepted for the Royal Academy summer exhibition of 1790 when Turner was 15. As an academy probationer, Turner was taught drawing from plaster