The oldest section of Copenhagen's inner city is often referred to as ''Middelalderbyen'' (the medieval city). However, the city's most distinctive district is Frederiksstaden, developed during the reign of Frederick V. It has the Amalienborg Palace at its centre and is dominated by the dome of Frederik's Church (or the Marble Church) and several elegant 18th-century Rococo mansions. The inner city includes Slotsholmen, a little island on which Christiansborg Palace stands and Christianshavn with its canals. Børsen on Slotsholmen and Frederiksborg Palace in Hillerød are prominent examples of the Dutch Renaissance style in Copenhagen. Around the historical city centre lies a band of congenial residential boroughs (Vesterbro, Inner Nørrebro, Inner Østerbro) dating mainly from late 19th century. They were built outside the old ramparts when the city was finally allowed to expand beyond its fortifications.