The monastery's katholikon dates to the 15th century, which is also when the monastery was probably founded, although it may have antecedents as early as 1271, when the ruler of Thessaly, John I Doukas, received horses in the locality.
The katholikon is of the Athonite variety of the cross-in-square church with two conchs, narthex, and exonarthex, with four attached chapels on each corner. The main church is dedicated to the Virgin Mary, and the chapels to the Transfiguration (southeast), the Holy Apostles (northeast), Saint Charalambos (northwest), and Saint John (southwest). Its interior decoration dates to three clearly discernible phases: the 16th–17th centuries, the 18th century, and the 20th century. The monastery served as a refuge for Greek rebels during the early stages of the Greek War of Independence, and was burned down by the Ottoman Turks, with the katholikon's roof and dome being rebuilt afterwards. The rest of the monastery buildings are of more recent construction, with the originals having been destroyed.
Since 1985, the monastery also houses the Oiti Natural History Museum (Μουσείο Φυσικής Ιστορίας Οίτης), dedicated to the geology, climate, flora and fauna of Mount Oeta and its national park.
- Koder, Johannes; Hild, Friedrich (1976). Tabula Imperii Byzantini, Band 1: Hellas und Thessalia (in German). Vienna: Verlag der Österreichischen Akademie der Wissenschaften. pp. 117–118. ISBN 978-3-7001-0182-6.
- Vasiliki Sythiakaki. "Μονή Αγάθωνος: Περιγραφή" (in Greek). Greek Ministry of Culture. Retrieved 19 September 2015.
- "Μουσείο Φυσικής Ιστορίας Οίτης" (in Greek). Municipality of Lamia. Retrieved 17 December 2015.