The earliest Fraumünster building recorded and identified in archaeological studies was constructed as the result of an endowment rom King Ludwig the German in 853. The first abbess was Ludwig's daughter Hildegard. The convent was home almost exclusively to women of noble birth. Until the Reformation the abbess was also the ruler of the city. The church as we know it today was constructed between the 13th and the 15th centuries. During the Reformation the last abbess handed over the church and all the abbey's other property to the city. It was only in 1728-1732 that the appearance of the Fraumünster was converted into that of a parish church when the south tower lost its spire and the height of the north tower was almost doubled to 80m. The tower was also fitted with a clock. The last major alteration to the church in the early 20th century under Gustav Gull was carried out after the demolition of the convent buildings on the site where the Town Hall now stands.