Theotokos Kosmosoteira

[1] The site, known as Bera (Greek: Βήρα, from a Slavic word for "marsh") was then uninhabited and densely overgrown location,[2] but the main church (katholikon) was apparently erected on the remains of an earlier, possibly ancient Roman building.

Isaac stipulated it as a cenobitic monastery for 74 monks, of whom 50 choir brothers (free from menial labour and dedicated to the church services), all over 30 years old.

[1] To support its operation and ensure its financial independence, Isaac endowed the monastery with extensive estates across Thrace.

[1] Isaac also built two bridges over the Evros river in the area, for whose upkeep the monastery's abbot was made responsible.

[3] The building shows extensive later repairs on the central apse and the prothesis, as well as the addition of four external buttresses.

[3] On the northern and southern walls are large representations of military saints, with features borrowed from Isaac's relatives of the Komnenos dynasty: his father Alexios I on the left on the northern side, and possibly his older brother Andronikos on the right; and his oldest brother John II Komnenos left and Isaac himself on the right on the southern side.

[3] Surviving frescoes include representations of the Presentation of Jesus at the Temple, the Pentecost, the Communion of the Apostles, the Theotokos praying, prelates and prophets, and six-winged seraphs.