Heritage Open Day: St Mary and St Margaret is at first sight a Georgian style church, one of the very few remaining in Birmingham. The church has a secret, however! Come and discover the Church within a Church and learn more about its past. St Mary and St Margaret is the parish church for Castle Bromwich but for many years was the private chapel to Castle Bromwich Hall. It is located in the Conservation area of Castle Bromwich comprising Castle Bromwich Hall, Castle Browich Hall Gardens and the church. The site has been occupied continuously since pre-roman times and has been place of worship for almost a thousand years.