It became a public garden in 1926 when Leicester Corporation started reclaiming land along the River Soar and the Grand Union Canal. The land belonged to Trinity Hospital and the county council, and the Corporation leased it to add to its own land and the site of the old West Bridge Mills. In 1937 the site was extended by leasing more Trinity Hospital land. The whole site now belongs to De Montfort Uni.
Trinity Hospital was founded in 1330 by Henry Earl of Lancaster to provide homes for 50 poor and infirm people. Some time later Henry's son enlarged the building, calling it his New Work. (The area is today called Newarke.) The establishment included a college of canons and a church. The foundation closed in 1548 during the Protestant Reformation and many of the buildings were demolished.
The associated hospital survived, however, and was renamed Trinity Hospital. It's been rebuilt twice, in 1776 and 1901, but the residents moved to a modern property in 1995. Then the building was renamed Trinity House ad is now part of the university campus.