Today the Church celebrates the Solemnity of the Assumption of the Mother of God. In the east this feast is called the Dormition of the Theotokos.
From Blessings of the Daily: A Monastic Book of Days by Brother Victor-Antoine d'Avila-Latourrette:
"This feast is considered, especially in the East, the most prominent of all the feasts celebrated in honor of the Mother of God. It is also one of the most ancient. In the Christian East, the feast is kept with great solemnity and is preceded by a two-week fast as preparation.
Some Christians, not of the Orthodox or Catholic tradition, have a difficult time trying to comprehend the mystery we are about to celebrate. After all, there is no testimony in the Scriptures concerning the death and Assumption of the Mother of God into heaven. Our belief is founded on sacred tradition, the belief of the ancient, undivided Church. . . . Saint Juvenal, bishop of Jerusalem around the time of the Council of Chalcedon, relates the tradition as it was believed by the Christians of Jerusalem: Mary died in the presence of all the Apostles (except Thomas), but when her tomb was opened at the request of Saint Thomas, it was found empty; where from the Apostles concluded that her body had been taken up to heaven."