In Norse mythology, a valkyrie (; from Old Norse valkyrja "chooser of the slain") is one of a host of female figures who choose those who may die in battle and those who may live. Selecting among half of those who die in battle (the other half go to the goddess Freyja's afterlife field Fólkvangr), the valkyries bring their chosen to the afterlife hall of the slain, Valhalla, ruled over by the god Odin. There, the deceased warriors become einherjar (Old Norse "single (or once) fighters"). When the einherjar are not preparing for the events of Ragnarök, the valkyries bear them mead. Valkyries also appear as lovers of heroes and other mortals, where they are sometimes described as the daughters of royalty, sometimes accompanied by ravens and sometimes connected to swans or horses. Valkyries are attested in the Poetic Edda (a book of poems compiled in the 13th century from earlier traditional sources), the Prose Edda, the Heimskringla (both by Snorri Sturluson) and the Njáls saga (one of the Sagas of Icelanders), all written—or compiled—in the 13th century. They appear throughout the poetry of skalds, in a 14th-century charm, and in various runic inscriptions. The Old English cognate terms wælcyrge and wælcyrie appear in several Old English manuscripts, and scholars have explored whether the terms appear in Old English by way of Norse influence, or reflect a tradition also native among the Anglo-Saxon pagans. Scholarly theories have been proposed about the relation between the valkyries, the Norns, and the dísir, all of which are supernatural figures associated with fate. Archaeological excavations throughout Scandinavia have uncovered amulets theorized as depicting valkyries. In modern culture, valkyries have been the subject of works of art, musical works, comic books, video games and poetry.