Constantine Simonides was an exceptionally skillful calligrapher who is allged to have sold spurious documents (as well as possibly some that were genuine) in England in the 1850s and 1860s. Among his clients were Sir Frederick Madden of the British Museum and the omnivorous collector Sir Thomas Phillipps. Simonides resided in the monasteries at Mount Athos between 1839 and 1841 and again in 1852, during which time he may have acquired or forged some of the manuscripts that he later sold. He was in England between 1853 and 1855 and then in France and Germany. In 1862 Simonides published in English journals his claim to have written the Sinaitic Codex, which the scholar Contantine von Tischendorf had discovered at Mount Sinai some years earlier and maintained had been written during the 4th century C.E.
From the description of Collection of papers relating to the Codex Sinaiticus : probably forged by Constantine Simonides, [ca. 1856-1863]. (Unknown). WorldCat record id: 122577022