Philotheou is built on a plateau on the northeast side of Mt. Athos near the monastery of Karakallou. It was founded towards the end of the 10th century, possibly by the monk Philotheos, from whom it received its name. the Catholicon dates from the year 1746 and was frescoed in 1752. A fire in 1871 destroyed the monastery save the Catholicon and the library. Its feast day is the Annunciation of the Virgin Mother. The most important relic of the monastery is the icon of Theotokos Glykofiloussa, the Crucifixion, a piece of the True Cross, the right hand of St. John Chrysostomos and others. Among those who lived in this monastery were St. Dionysios, who later founded the monastery of Agia Trias on Olympos and the apostle Kosmas Aetolos. The library contains around 250 manuscripts and many printed works. The monastery is the 12th in the hierarchy of Mt. Athos.

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