historically, with Saint Sulien, with some scholars suggesting that they were the same historical character. The facts that they lived in different Celtic states, and had different feast days from antiquity, make this suggestion unlikely. Place names Today Tysilio's name is remembered in several church and place names in Wales, including Llandysilio in Powys, Llandissilio in Pembrokeshire, Llandysiliogogo in Ceredigion and Llantysilio in Denbighshire. Most famously it appears in the longest place name in the United Kingdom, Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch, part of which (shown bold here) means the Church of St. Tysilio. The name, however, is a late 19th-century invention for the burgeoning tourist industry in the area. References Roberts, Brynley F. (ed.). Brut y Brenhinedd (Llanstephan MS 1), Brut y Brenhinedd. Llanstephan MS. 1 version. Selections. Mediaeval and Modern Welsh series 5. Dublin, 1971. Extracts and discussion. Simpson Jones, T. and Owen, R. (1901), "A History of the Parish of Guilsfield (Cedigva)", Montgomery Collections; 31, 129–200. Further reading People from Powys Welsh royalty Medieval Welsh saints 640 deaths Year of birth unknown