The most important monastery of the region of Serrhai was founded in the 13th century in a gorge of Mount Menoikion, not far from the city of Serrhai. It was laid out following the plan of most Athonite monasteries, i.e. it had encircling walls to which other structures were later added, a sturdy square tower, chapels, and a katholikon with 14th century wall-paintings.
As the spiritual centre of Hellenism in eastern Macedonia, during the Balkan wars the monastery of Timios Prodromos (Saint John the Baptist) provoked the fury of the Bulgarians, who took pains to strip it of its historic treasures. Greek historical documents and in particular the monastic library were carried off to Sofia in their entirety in 1912. The quest for these invaluable sources of Macedonian history has since occupied, as it continues to occupy, much scholarly research.