The Codex Vaticanus (The Vatican, Bibl. Vat., Vat. gr. 1209; no. B or 03 Gregory-Aland, d 1 von Soden), is one of the oldest extant manuscripts of the Greek Bible (Old and New Testament), one of the four great uncial codices. The Codex is named after its place of conservation in the Vatican Library, where it has been kept since at least the 15th century. It is written on 759 leaves of vellum in uncial letters and has been dated palaeographically to the 4th century.