을 타고

by riding; on (a vehicle or animal)

→ 을
phrase Common #6,017
by riding; on (a vehicle or animal) 을 marks the thing being ridden or taken, and 타고 connects it to what happens next. After a vowel, 를 is used instead of 을.
KO: 저는 말을 타고 공원에 가요.
EN: I go to the park on horseback.