forts and hawthorn trees, also known as fairy trees, are places where fairies are thought to reside. Thus, to tamper with these sites is seen as hugely disrespectful to the fairies. Hawthorn tree There are several trees sacred to Ireland, but the lone hawthorn (aka the "may" tree) is particularly considered a fairy haunt, and patches underneath where the grass have worn down are reputed to be due to fairies dancing. Though literary fiction more than folklore, two consecutive poems by Samuel Ferguson, "The Fairy Thorn" and "The Fairy Well of Lagnanay" describes the lone Fairy Hawthorn (The Whitethorn). Fairy mounds The notion that Irish fairies live in fairy mounds (fairy forts, fairy hills) give rise to the names aos sí or daoine sídhe ('people of the sidhe [fairy mound] '). In the instance of "The Legend of Knockgrafton" (name of a hill), the protagonist named Lusmore is carried inside the fairy "moat" or rath by the fairy wind (). Heroic sagas Other classic themes in Irish folktale literature include Cú Chulainn, Children of Lir, Finn MacCool, from medieval heroic and tragic sagas. Folklore material in the 'Pre-Croker period', according to Bo Almqvist's reckoning, do tentatively include various Medieval written texts (the heroic tales in the Ulster Cycle, Finn Cycle, the Cycle of the Kings, and the hagiography of St. Patrick and other saints, etc.), with the proviso that these works can no longer be considered intact folk legends, given the accrued literary layers of the "fanciful and fantastic". However they are an excellent well-source of comparative study, as collected folktales are sometimes traceable to these medieval sagas. An example is the tale of Cú Chulainn's horse remnant in the legend type of "The Waterhorse as Workhorse" (MLSIT 4086), or so argued by C. W. von Sydow. In the 20th century, the Irish Folklore Commission collected a large corpus of such romantic heroic sagas, particularly the stories of Fionn Mac Cumhail and the Fianna. History of collecting Early collectors For most of the 19th century, collection of Irish folklore was undertaken by English-speakers, and the material collected were recorded only in English. Thomas Crofton Croker who compiled Fairy Legends and Traditions of the South of Ireland (1825–28) is considered one of the earliest collectors. Croker is the first among the significant "antiquary-folklorists" (the label applied by Richard Dorson) to emerge from mere antiquarians. Tales in the Irish language The Irish-speaking