isseosseoyo (있었어요) is the past polite/전댓말 form of 있다 and means "there was/were." It is also in some set phrases like masitda (맛있다) "to be good" and jaemiitda (재미있다) "to be fun." 재미있었어요 - Jaemi isseoseoyo. - That was fun. 지난주 나의 집에 조부모님이 있었어요. - Jinan ju naui jipe jobumonimi isseosseoyo. - My grandparents were at my house last week.