 He proposed locations for each tribe, without attempting to locate each one, and suggested that some Anglo-Saxon peoples were missing from the document.Birch, in his paper "An Unpublished Manuscript of some Early Territorial Names in England", announced his discovery of what became known as Recension A, which he suggested was a 10th or 11th century copy of a lost 7th-century manuscript.He methodically compared all the publications and manuscripts of the Tribal Hidage that are available at the time and placed each tribe using both his own theories and the ideas of others, some of which (for instance when he located the "Wokensætna" in Woking, Surrey) are now discounted.