History Hotel is one of Windsor’s oldest buildings and it started off just as a simple inn named The Mermaid Inn during the 1500s. It was used to accommodate troops in the mid 1600s during the time of the civil war. In 1786 its owner Richard Martin postmaster of Windsor and Hackney, and man to His Majesty, was bestowed a royal warrant. It was then it was renamed The Castle Inn. The castle was purchased in 1913 by the Public House Trust Company who significantly developed and expanded the building. The Hotel first received a listing in the AA handbook. In 2015 the hotel opens up as part of the MGallery Collection.