TASK DEFINITION: Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.
PROBLEM: Who was the father of Edward the Elder, the Anglo-Saxon King from 899 to 924?

SOLUTION: edward the elder

PROBLEM: Aragon and Castile joined to form which country?

SOLUTION: aragon

PROBLEM: Who plays the Dowager Countess of Grantham in the TV series 'Downton Abbey'?

SOLUTION:
downton abbey