XIR216475 Fol.251v Finger counting from 1 to 20000, from \'De numeris. Codex Alcobacense\' by Rabanus Maurus (780-856) (vellum) by Carolingian School (9th century); Instituto da Biblioteca Nacional, Lisbon, Portugal; (add.info.: also known as Hrabanus or Rhabanus, was a Frankish Benedictine monk, the archbishop of Mainz in Germany and a theologian; Codex from a collection of 461 codices from the library of the Cistercian monastery of Santa Maria de Alcoba癟a, Portugal); out of copyright.