From the Writer's Almanac:
The anniversary of the Norman invasion of 1066. It was this week in 1066 that William the Conqueror of Normandy first arrived on British soil. The French-speaking Normans eventually defeated Old English-speaking Saxons at the Battle of Hastings on October 14, 1066 — which had a larger and more pronounced effect on the development of the English language than any other event in history. Within the course of a few centuries, English went from being a strictly Germanic language to one infused with a large Latinate vocabulary, which came via French.
The English word literature comes down from the Old French lettre. In the singular, the word in French refers to a member of the alphabet; when it's plural, it's as broad as it is in our phrase "Arts and Letters," encompassing literature and culture.
The pen with which we write may be mightier than the sword, but it was still a sharp object, at least when it first came into English from the Old French penne, "a feather with a sharpened quill." It was dipped in enque, which surely was spilled sometimes. This Old French word for ink came from a Latin word that described the purple fluid meant for a very specific use: the Roman emperor's official stamp of approval, his John Hancock.
Various genres of English literature derive their names from French roots, some of which ultimately derived from Greek. Poet, for example, we got from the Old French word poete, which entered French from Greek via Latin. In Greek, there's poiein, a verb meaning "to create." And in Greek there is poetes, "maker, poet." In Middle English, "poetry" at first referred to creative literature as a whole.
Tragedy in English is from the Old French tragedie via Latin from Greek tragoidia. The reasoning behind the Greek roots (tragos, meaning "goat" and oide "ode, song") is not entirely clear. On that note, mystery, from Old French mistere, was a word first used in English with the sense of "mystic presence" or "hidden religious" symbolism.
Comedy at first referred in English to a genre of stories in which the ending was a happy one. It also came into Middle English through Old French, via Latin from Greek, where it's a compound of the words "revel" and "singer." Comedian first referred to a person who wrote comic plays, and then — in the late 1800s — developed the sense of a person who stands in front of an audience and tells jokes.
Journal is from Old French jurnal, or "belonging to a day." At first, it was a sort of reference book that contained the times of daily prayers. In the 1600s, it acquired the meaning of "diary" and later became associated with newspaper titles and lent its root to journalism.