The Dionysius Monastery  is on the southwestern side of the peninsula. Dionysiou ranks fifth in the hierarchical order on Mount Athos and is dedicated to St. John the Baptist.

Dionysius Monastery was founded in the fourteenth century by St. Dionysios of Koreseos. The golden bull (chyrsobull) authorizing the founding of the monastery was signed in 1374 by Alexios II Comneno. A treasure, the bull is kept in the monastery. Construction proceeded with financial aid from emperor Alexios III Comnenos.

The monastery is built along the western coast of the peninsula on a rocky cliff high above the sea and overlooking a deep wooded ravine. In 1535, the monastery was swept by fire destroying it. Reconstruction began quickly and by 1547 the principal church of the monastery, the katholikon, had been built and painted with several murals by the Cretan painter Tzortis. A golden iconostasis was added in the eighteenth century. Around the katholikon are number of chapels including one that is dedicated to the Virgin Mary. Inside the monastery walls, a 25 meter high (80 feet) defensive tower was built in 1520. The tower was used periodically for safe keeping of the monastery's library. A dynamic community of monks now inhabits Dionysiou and has undertaken the job of renovating and redecorating the older buildings.

The Abbot of the monastery since 1989 is Petros, the monastery is inhabited by 45 monks.

The monastery library contains many old documents, including 804 codices and more than 5,000 old printed books. Among the holdings are Gospels from the eleventh century as well as chrysobulls (golden bulls) and manuscripts. Among these manuscripts is an illuminated Gospel from the thirteenth century.

The relics of St. Niphon, Patriarch of Constantinople, are housed in a special crypt in the katholikon.

Miracle-working icons within the monastery

The icon of Theotokos (Myrovlitissa) is considered to be one of 70 icons belonging to Luke The Evangelist. It’s painted with wax and mastic. Akathist to Theotokos is read daily in front of the icon. According to the myth it was carried around the walls of Constantinople during it’s siege by Arabs in 626. The icon also was also in the avant-garde of Michael VII Paleolog army. The icon was granted to the monastery by the Emperor Alexey III of Trapezund  (1337-1390) in honour of it’s foundation.

In 1592 the icon was abducted by the pirates but they had to bring it back because of  the storm. In 1767 the icon was stolen again by the bandits from Dalmatia. The Greek shepherds captured them and transferred the icon to Skopelos whose inhabitants didn’t wish to give the icon back to the monastery but had to do it after the epidemy developing on the island.