Historical

Lake Tana -an older variant is Tsana, Ge'ez ጻና Ṣānā; sometimes called "Dembiya" after the region to the north of the lake) is the source of the Blue Nile and is the largest lake in Ethiopia. Located in Amhara Region in the north-western Ethiopian Highlands, the lake is approximately 84 kilometers long and 66 kilometers wide, with a maximum depth of 15 meters, and an elevation of 1,788 meters. Lake Tana is fed by the Lesser Abay, Reb and Gumara rivers; and its surface area ranges from 3,000 to 3,500 km,² depending on season and rainfall. The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile. This controls the flow to the Blue Nile Falls (Tis Abbai) and hydro-power station

The lake has a number of islands, whose numbers vary depending on the level of the lake; it has fallen about 6 feet (1.8 m) in the last 400 years. According to Manoel de Almeida (a Portuguese missionary in the early 17th century), there were 21 islands, seven to eight of which had monasteries on them "formerly large, but now much diminished." When James Bruce visited the area in the later 18th century, he noted that the locals counted 45 inhabited islands, but stated he believed that "the number may be about eleven."A 20th-century geographer named 37 islands, of which he believed 19 have or had monasteries or churches on them.

Remains of ancient Ethiopian emperors and treasures of the Ethiopian Church are kept in the isolated island monasteries (including Kebran Gabriel, Ura Kidane Mehret, Narga Selassie, Daga Estifanos, Medhane Alem of Rema, Kota Maryam and Mertola Maryam). On the island of Tana Qirqos is a rock shown to Paul B. Henze, on which he was told the Virgin Mary had rested on her journey back from Egypt; he was also told that Frumentius, who introduced Christianity to Ethiopia, is "allegedly buried on Tana Cherqos." The body of Yekuno Amlak is interred in the monastery of St. Stephen on Daga Island; other Emperors whose tombs are on Daga include Dawit I, Zara Yaqob, Za Dengel and Fasilides. Other important islands in Lake Tana include Dek, Mitraha, Gelila Zakarias, Halimun, and Briguida.

The monasteries are believed to have been built over earlier religious sites. They include the fourteenth-century Debre Maryam, and the eighteenth-century Narga Selassie, Tana Qirqos (said to have housed the Ark of the Covenant before it was moved to Axum), and Ura Kidane Mehret, known for its regalia. A ferry service links Bahir Dar with Gorgora via Dek Island and various lakeshore villages.

Lake Tana - Churches and Monasteries 

The Lake Tana area was important in the fourteenth, fifteenth and sixteenth centuries in view of its role in maintaining the Christian faith against contemporary pressures, and the rise of the Solomonic Dynasty which patronized the building of churches and monasteries. Many of the earliest manuscripts and precious examples of ecclesiastical art as well as royal objects were safely stored in their treasuries. At the same time, new religious arts were developed and displayed in the churches. The oldest of these forty or so churches have their origins in the fourteenth century. They reflect the native building tradition in their round shape, materials and building techniques. Each one consists of three parts: the inner sanctuary, the inner ambulatory and the outer ambulatory. The outside walls of the sanctuary are usually covered with magnificent paintings. Seven of the most accessible and representative of these churches, still serving their original function, have been selected for the international campaign: Kebran Gabriel, Ura Kidane Mehret, Narga Selassie, Daga Estifanos, Medhane Alem of Rema, Kota Maryam and Mertola Maryam.