Downtown Ajax was farmland until 1941 when Defence Industries Limited (D.I.L.) assembled 2,985 acres of land to form one of the largest munitions plant in the British Empire during World War Two. At its peak D.I.L. employed 9,000 men and women who were recruited from all across Canada. It was the D.I.L. workers that came up with the name Ajax which paid tribute to the British war ship HMS Ajax. Many Ajax streets are named in honour of the men who served on HMS Ajax as well as two other heralded British warships, HMS Exeter and HMS Achilles. For a brief time after the war the D.I.L. plant was repurposed as a supplementary campus for the University of Toronto engineering school. Many of the students were returning war veterans. In 1949 the campus closed due to declining enrolment. The 1950s marked the beginning of what is now known as Downtown Ajax. This is when the   Ajax Shopping Centre, Ajax and Pickering General Hospital and Ajax Community Centre were built to serve the growing population. In 1974 Durham Region was formed and downtown Ajax was chosen as the location for the Town Hall and Main Library