Carlos Magno e a renovação do império; A fragmentação do império e as novas invasões; O mundo do feudalismo; Os Otões e a restauração imperial; A luta entre o pontificado e o império; As três primeiras cruzadas; A era do "Dominium Mundi" e o fracasso da teocracia pontifícia e da ideia imperial; Cluny e Cister. As ordens mendicantes; A escolástica cristã; A síntese medieval. As universidades. Dante; Bizâncio, da iconoclastia ao império latino de Constantinopla.
Various is the correct author for any book with multiple unknown authors, and is acceptable for books with multiple known authors, especially if not all are known or the list is very long (over 50).
If an editor is known, however, Various is not necessary. List the name of the editor as the primary author (with role "editor"). Contributing authors' names follow it.
Note: WorldCat is an excellent resource for finding author information and contents of anthologies.