A convalescent hospital and rehabilitation centre in the Grange district of Edinburgh, the Astley Ainslie Hospital opened in 1923 in a parkland setting, 2 miles (3 km) south of the city centre. It was established with a bequest from David Ainslie of Costerton, a wealthy Midlothian sheep breeder and landowner who died in 1900 leaving a substantial fortune to create an institution where patients from the Edinburgh Royal Infirmary could recuperate. Named after Ainslie's nephew, it was built in the grounds of the 19th-century mansions of Canaan House, Canaan Park, Millbank, Morelands, Southbank and St. Roque's, most of which remain as administrative blocks. The area, once part of the Borough Muir, was the site of St Roque's Chapel, built c.1500 by King James IV. Canaan Park was a residence of the Forbes of Pitsligo. Millbank had been the home of Neilson family. In 1820, Anne Neilson married the Sultan of the Crimea here. He had been sent to Edinburgh by Tsar Alexander of Russia to receive a Christian education. The couple settled in Morningside. It was later purchased by surgeon James Syme (1799 - 1870). It was here in 1856 that Syme's daughter married Joseph Lister (1827 - 1912) and where author Thomas Carlyle (1795 - 1881) recuperated in 1866 after being operated on by Syme. The house proved unsuitable as a hospital ward and was quickly demolished, to be replaced by the Millbank Pavilion, one of several new blocks built to provide fresh air and open access to the grounds promoting the recovery of patients.
The Occupational Therapy Unit here was the first of its type in Scotland, established in 1930. On the creation of the National Health Service, the Astley Ainslie Hospital came under the management of the South Eastern Regional Hospital Board. The Charles Bell Pavilion was built in 1965 and now houses a notable Rehabilitation Studies Unit. The Faculty of Health and Life Sciences of Napier University was established here in the former nurse's home in 1999 and mobility and prosthetics services came from the former Princess Margaret Rose Orthopaedic Hospital in 2002. Today, the hospital has more than 200 beds and is run by Lothian Primary Care NHS Trust.