This is the 3397th most frequent Korean word.
당시에는
"At that time."
It is used to refer to a specific time in the past when the mentioned belief was held.
당시에는 모두가 그 계획이 성공할 거라고 믿었어요.
At that time, everyone believed that the plan would succeed.
It highlights a particular feeling or reaction that occurred specifically during that moment in the past.
그 소식을 들었을 때 당시에는 정말 충격적이었어요.
When I heard the news, it was really shocking at the time.
It serves to contrast past conditions with the present, specifying that particular period without the internet.