Conversation so far:
Where was Arthur Wellesley, 1st Duke of Wellington born at?
His birthplace is uncertain.
He was most likely born at his parents' townhouse, 24 Upper Merrion Street.
Did he have siblings?
CANNOTANSWER.
Did he go to college.?
He then enrolled at Eton College, where he studied from 1781 to 1784.

Question: What did he study?
Self-contained rewrite: What did Arthur Wellesley study at Eton College?