In Western literary tradition, oral literature played several important parts in unifying all the literary traditions, from Latin and Greek, to the disparate tribal cultures. An excellent examples lies in the Arthurian traditions, influences by Cretien de Troyes, etc., but beginning with The Mabinogion, a Welsh narration of the exploits of the original Arthur and his knights, transformed from the oral traditions into written literature in the Middle Ages. Another example: thousands of oral folk stories that were gathered into Grimm’s Fairy Tales. Folk songs and oral legends of all cultures are incorporated into the written literature of that culture, not only in plot and character, but also in rhythms, in folk idioms, and in cultural mores. On the continent of Africa, a fairly recent effort to consolidate African literature as a special area of study has revealed that, although the lack of a common language may have thwarted written literary development, that lack has been more than made up for by the extremely rich oral traditions of all the African cultures, and several common historical themes, notably colonialism, slavery, and exploitation of natural riches, have unified the modern written literature of Africa which has taken advantage of all the oral literature of the continent.