Marienburg Castle is a Gothic revival castle in Lower
Saxony, Germany. It is located 15 kilometres (9.3 mi) north-west of Hildesheim,
and around 20 kilometres (12 mi) south of Hanover, in the municipality of
Pattensen, Hanover. It was a summer residence of the House of Guelph. It was
once given as a birthday present by King George V of Hanover (reigned
1851–1866) to his wife, Marie of Saxe-Altenburg.