The true originator and date of the longer version of the name is less certain, however: an ecclesiastical directory published a few years before the claimed renaming gives what it calls the "full" parish name in the slightly differing form of Llanfairpwllgwyngyllgogerbwlltysiliogogo ("St Mary's church of the pool of the white hazels over against the pool of St Tysilio Gogo [Tysilio of the cave]"),[14] while Llan-vair-pwll-gwyn-gyll-goger-bwll-dysilio-gogo appears in a paper on placenames published in 1849, its author noting that "the name was generally abridged" by locals.[7] While the addition regarding the Swellies is supposed only to have been made in the 1860s, early 19th century guidebooks had already suggested a derivation of the element pwllgwyngyll from pwll, gwyn and gwyll ("gloomy raging pool"), in reference to the Swellies.[25]