The present church building dates from the 14th and 15th centuries, but a previous church on the site was built by the Normans and served Chester castle. Built around 1443, the south chapel was originally owned by the Earl of Shrewsbury, and was damaged in 1645 during the civil war, collapsing in 1661 and being rebuilt in 1693. Later, in order to provide a clear line of fire during the Jacobite rebellion of 1745, the upper stage of the tower was demolished by Lord Cholmondeley. In 1861-62 the church was restored by James Harrison, and again by J.P. Seddon in 1890-92, when the north porch was rebuilt in memory of Randle Holme III. In 1930 the aisle roofs were rebuilt. The church was decommissioned in 1972.
For a fuller history, see the original Wikipedia entry HERE.
Or, for a fascinatingly historical description of St Mary’s download this excerpt from Bertram C A Windle’s superb book of 1903 - Chester, A Historical and Topological Account of the City - HERE.