The British royal family's surname, adopted in 1917, comes from which castle?

Casper Van Dien played a young soldier battling giant bugs in which 1997 film? Cassandra Peterson co-wrote and starred in a 1988 film about which "Mistress of the Dark"? Cassius Clay, playing himself, ends the career of boxer Mountain Rivera in which 1962 film? Castle Clinton in New York City was originally a fort, renamed in 1815 for which mayor? "Castle Richmond" (1860) is a novel by which author of "Barchester Towers"? Castles offered great protection until the 1400s, when which weapons came into wide use? Castor and Pollux are known as the twin sons of which god? Which children's author was born on March 2, 1904, a date now celebrated as Read Across America Day?