Complex sentence: Dresden Castle (German: Dresdner Residenzschloss or Dresdner Schloss) is one of the oldest buildings in Dresden and has been the residence of the electors (1547--1806) and kings (1806--1918) of Saxony.
Split into simpler sentences: Dresden Castle (German: Dresdner Residenzschloss or Dresdner Schloss) is one of the oldest buildings in Dresden. For almost 400 years, it has been the residence of the electors (1547--1806) and kings (1806--1918) of Saxony.