The gate of Armenon or Larmenon, is one of the monuments that signals the historic succession in the area of Styra. It is preserved on top of Ayios Nikolaos of Diakofti (, in the mountain Kliosi in Styra height 450 m.).
The gate, that constitutes the emblem of Municipality of Styra, is an impressive megalithic construction made with Cyclopean Stones, while the remains of ancient cyclopean wall can be noted on the left and right side of it.
In later years, Western Europeans built a castle over the walls of the ancient Acropolis of Styra, that was occupied in early 1300 A.D. by the Catalans , who sold the fortress to the Enetians in 1373. It’s use continued after the occupation of Evia in 1470 from the Ottomans.
An important monument, highly visitable, that points out the importance of the area.
Further important historical monuments of the medieval and modern periods are the two small churches found inside it the castle. The stone-covered church of St. Nicolas, built in the early 1800s, is located at the peak of the hill on which the castle lies, and the hill takes its modern name from the church. The Church of Virgin Mary of the castle was, as two inscriptions near the entrance testify, rebuilt in 1746 on the ruins of an earlier single-aisle covered basilica. Other small churches of the area include the little historic church of St. Anne at Kapsala, built during the period of Ottoman occupation, and the cruciform-shaped Byzantine temple of the SS Theodore at Reouzi (a hamlet of the Municipality of Styra).