The name "Scandia", later used as a synonym for "Scandinavia", also appears in Pliny's "Naturalis Historia" ("Natural History"), but is used for a group of Northern European islands which he locates north of Britannia. "Scandia" thus does not appear to be denoting the island Scadinavia in Pliny's text. The idea that "Scadinavia" may have been one of the "Scandiae" islands was instead introduced by Ptolemy (c. 90 – c. 168 AD), a mathematician, geographer and astrologer of Roman Egypt. He used the name "Skandia" for the biggest, most easterly of the three "Scandiai" islands, which according to him were all located east of Jutland.