The Monastery of the Great Lavra, (Greek: Μεγίστη Λαύρα, Megísti Lávra) is located on the Athos Peninsula in northern Greece. The Great Lavra was founded in 963 by St. Athanasius the Athonite. It is ranked first in the hierarchical order of the Mount Athos monasteries located on the peninsula. It is considered the mother monastery of Mount Athos.
The Great Lavra was one of the earliest of the monasteries built on the Athos Peninsula. It was built by St. Athanasius with the financial support of the emperors in Constantinople including Nikephorus Phocas, Romanos II, and Ioannis Tzimikes. Nikephoros had promised Athanasius that he would soon become a monk of Great Lavra but the circumstances and his death canceled those plans. However, a permanent imperial grant, which was doubled by John I Tzimiskes, allowed the integration of the buildings. St. Athanasius is considered to be the founder of athonite monasticism.
The monastery is built in the form of a small medieval town within a strong walled fortress with fifteen towers. There are 37 chapels associated with the Lavra. These are located both within and without the fortress walls. The central church within the Lavra, the Katholikon, was among the first structures built starting in 963. It is a domed four-column church that was modified over time to a more cruciform shape. The church was initially dedicated to the Annunciation of the Blessed Virgin Mary, but was re-dedicated to St. Athanasius in the 15th century. His tomb is located in the chapel of the Forty Martyrs which is located next to the narthex of the Katholikon.