Old Nubian is preserved in at least a hundred pages of documents, comprising both texts of a Christian religious nature and documentary texts dealing with state and legal affairs. Old Nubian was written with a slanted uncial variety of the Coptic alphabet, with the addition of characters derived from Meroitic. These documents range in date from the 8th to the 15th century AD. Old Nubian is currently considered ancestral to modern Nobiin, even though it shows signs of extensive contact with Dongolawi. Another, as yet undeciphered Nubian language has been preserved in a few inscriptions found in Soba, the capital of Alodia. Since their publication by Adolf Ermann in 1881, they are referred as 'Alwan inscriptions' or 'Alwan Nubian.'