The Holy Monastery of Dionysiou, or 'Nea Petra', stands on a narrow and precipitous rock at a height of 80 metres above the sea, between the Gregoriou and Aghiou Pavlou Monasteries. The founder of the Monastery was the Blessed Dionysius from Korysos near Kastoria. Dionysius, with much toil and in the face of many difficulties, managed to gather the resources to build the Monastery in the second half of the 14th century. His efforts were supported by the generous sponsorship of Alexius III Comnenus, Emperor of Trebizond, who was encouraged in this by the Metropolitan of the city, Theodosius, who was Dionysiou’s brother. This policy of lavish sponsorship of the Monastery was continued by the Palaeologue Emperors and later by many Princes of Moldo- Wallachia.
The Patriarch Antonius IV officially gave the Monastery the title of 'Patriarchal' in 1389, and in this way it acquired an autonomous existence. Linked with the Dionysiou Monastery is the important figure of St Niphon, Patriarch of Constantinople, who became a monk of Dionysiou in the mid 15th century and after many vicissitudes returned to the monastery of his repentance where he lived until his death. In the early 16th century, Radul, Prince of Moldavia, and his successor Neagoe Basarab built the Monastery's aqueduct and tower. In 1539 a fire, perhaps the worst in the history of the Monastery, reduced to ashes a large part of its buildings, which, however, were soon replaced and extended. In the 16th and 18th centuries, the Monastery, because of economic difficulties, became idiorrhythmic, but in the 19th century returned irrevocably to the coenobitic system.
The katholikon of the Monastery, dedicated to the Nativity of St John the Baptist, was built at the same time as the Monastery, but was ruined by a fire in 1534. The church which replaced it was built immediately after 1540. Its wallpaintings are the work of a representative of the Cretan School, Tzortzis, dating from around 1546. Of particular note are the gilded sanctuary screen and the wall-paintings of the Apocalypse, the oldest complete portrayal of the Apocalypse in the Orthodox world.
Dionysiou possesses the miraculous icon known as Our Lady of the Salutations or Our Lady of the Akathistos Hymn. Seven kellia are subject to the Monastery, and, also a considerable number of kathismata. It has eight chapels and six outlying chapels; it also owns the metochi of Monoxylitou, which it received from the Lavra Monastery in the mid 17th century. Dionysiou occupies fifth place in the hierarchy of the Athonite monasteries. Among its treasures it has many relics of saints, the most important being the right hand of St John the Baptist and the relics of St Niphon. Other interesting possessions include a relief of the Crucifixion in ivory, dating from the 10th century, embroideries, sacred vessels, and vestments. The library contains 1,100 manuscripts, some of them illustrated, and more than 15,000 books, including priceless incunabula. In the present century, the Monastery has produced notable ascetics and scholars; today it has a community of around 50.