The architecture of Liverpool is rooted in the city's development into a major port of the British Empire. It encompasses a variety of architectural styles of the past 300 years, while next to nothing remains of its medieval structures which would have dated back as far as the 13th century. Erected 1716-18, Bluecoat Chambers is supposed to be the oldest surviving building in central Liverpool.There are over 2,500 listed buildings in Liverpool of which 27 are Grade I and 85 Grade II* listed.