The ecclesiastical museum, which opened in 1978, is in the metropolis, at the center of Mytilene opposite the Church of Ayios Therapon, and consists of 2 halls. In these halls there are relics belonging to the island's monasteries such as manuscripts, books, utensils, icons, shrines, vestments etc. It houses significant ecclesiastical objects from the Byzantine and post-Byzantine era. Among its exhibits are valuable icons, sacerdotal vestments, fretwork ecclesiastical items, rare manuscripts and missals. The collection of the holy icons covers the period from the 13th to the19th centuries. There are also crosses carved in wood, sacred utensils made of silver and gold, old gospels and a lot of valuable objects of great historic value.
Extremely impressive are three artistic icons of large dimensions, painted by unknown hagiographers, those of Pantocrator (Jesus Christ), of Ayios Ioannis Theologos (Saint John the Theologian ) and of Ayios Georgios (Saint George).
In the first hall, among other exhibits, the visitor can see the mantle of the national martyr patriarch Grigorios V. and the sleeves of Chrysostomos of Smyrna. The walls in the 2nd hall are decorated with icons, some of which are works of the famous hagiographer Poulakis. In the same building there is also the ecclesiastical library of Samos.
On the eastern side of the island, on the sea front the Cathedral contains a Byzantine Museum with historical interest and exhibits of considerable artistic gathered from the monasteries of the island. It includes post-Byzantine icons, ossuaries, chalices, vestments, Patriarchal Bulls holy vessels, lead seals, on parchment lead seals and many other ruins.
In the same building another room is the Cathedral Library, with a great number of unusual books, bibles, monastery chronicles, imperial golden bulls etc.