Before colonisation, this site was home to the Eora people. Foreshore middens suggest the importance of the site for gatherings and ceremonies. There are a number of rock carvings on the site however, there seem to be varying opinions of their dates and/or authenticity due to the fact that there have been a number of obviously recent additions including dates and names added around the carvings.Regardless of the circumstances, the rock carvings are significant. Callan Park as it stands is a heritage listed site in Lilyfield. It is a large parkland of 104.5 acres and is equivalent to the size of the Sydney Botanical Gardens. The area was originally a private residence owned by John Ryan Brennan who purchased the property in 1839. Brennan was the Crown Solicitor and the Police Magistrate. For reasons that are unclear, he named the area the Garry Owen Estate. In 1864 Brennan was declared bankrupt and was forced to sell the property. A businessman named John Gorton purchased the property and named it Callan Park after his home in Scotland and in 1873 he subdivided the land for auction as a new waterfront suburb.In 1878 the Colonial Government bought the whole 104.5 acres as a site for a new "lunatic asylum" to be designed according to the enlightened views of the American Dr Thomas Kirkbride. Colonial Architect James Barnett worked with Inspector of the Insane Dr Frederick Norton Manning to design and create a group of some twenty neo-classical buildings, completed in 1885 and subsequently named the Kirkbride Block, offering progressive patient care.Callan Park Hospital for the Insane was proclaimed a separate institution from Gladesville .The temporary wards were occupied in 1879 and provided accommodation for 48 patients from Gladesville, one from the Parramatta Hospital and 16 admitted from the Water Police Court, making 114 patients. One of these wards became Male Ward 7. The hospital was constructed between 1880 and 1884 with the main complex being completed in 1885. It was the first hospital for "moral therapy" treatment in Australia. It received the first patient in October 1884.Moral therapy was an approach to mental disorder based on humane psychosocial care or moral discipline deriving partly from psychiatry or psychology and partly from religious or moral concerns.Moral therapy treatment had begun earlier in 1876 with the 44 patients in Garry Owen House. Yet constant overcrowding, staffing difficulties, and inadequate funding increasingly made the hospital a place of incarceration. The design for the permanent hospital was a collaborative effort between Colonial Architect James Barnett and Dr Frederick Norton Manning Barnet. Manning based the design of Callan Park on drawings from the Chartham Downs Hospital in Kent. Five male and five female wards were designed to accommodate approximately 600 patients. The hospital was named the Kirkbride Block.In 1905 Inspector-General Eric Sinclair, Manning's successor, opened special admission wards for curable cases in the Manning/Barnet designed Female Cottage Hospital, which was separate from the main hospital. Between 1907 and 1910 a new admission ward, designed by the architect Walter Liberty Vernon, brought the number of cottage wards to four. The new admission facility was the forerunner of voluntary treatment without committal. Callan Park became the first mental hospital to have a laboratory and clinical rooms for 'scientific work' which started the studies of mental diseases in New South Wales.Garry Owen House was also used for patients for many years and later became a nurses training School.In 1976 Callan Park was amalgamated with the adjoining Broughton Hall Psychiatric Clinic to become the Rozelle Hospital, and building work on the original hospital almost ceased. Since 1994, the facility has been formally known as Rozelle Hospital. In April 2008, all Rozelle Hospital services and patients were transferred to Concord Hospital.The buildings in Callan Park are fine examples of architecture. Built of sandstone mainly quarried on site, most have slate roofs, timber floors, and copper down pipes. The verandahs are supported by hundreds of cast iron columns acting as down-pipes for water which is fed into an underground reservoir.Some historical buildings in Callan Park have been vacated and are now steadily being restored.After extensive renovations in 1996, the Kirkbride Complex which housed the former hospital became the Sydney College of the Arts . The NSW Writer's Centre is also located in Callan Park. This used to be a 2-storey Greek Revival House but due to many alterations that were made over the years it has changed however, enough of the original House remains to make it one of the most important heritage buildings in the municipality.The "Bay Run", a 7km walking and running track runs through the park along the foreshore of Iron Cove. The track is a collaboration between Canada Bay and Leichhardt Councils and has proved to be a popular leisure and health initiative.