Чрез несколько минут карета остановилась у дворца. Марья Ивановна с трепетом пошла по лестнице. Двери перед нею отворились настежь. Она прошла длинный ряд пустых великолепных комнат; After a few moments the coach stopped before the Palace. Marya Ivanovna went up the stairs, trembling. The door in front of her was opened wide. She crossed a long suite of empty and sumptuous rooms.

How to translate "отворились"? That means the door was opened by servants when Marya approached it, not that it was open from the beginning.