The Faerie Queene was written over the course of about a decade by Edmund Spenser. He published the first three books in 1590, then the next four books (plus revisions to the first three) in 1596. It was originally intended to be twelve books long, with each book detailing a specific Christian virtue in its central character. When he presented the first three books at the court of Queen Elizabeth, Spenser was looking for the prestige, political position, and monetary compensation he believed the work merited. However, he came away disappointed by the relatively small stipend (to his mind) that he received, and attributed his lack of spectacular success with Elizabeth to her advisor and Spenser's political opposite, Lord Burghley.
In Books Four through Six, Spenser seems to change the direction of the epic somewhat, possibly curtailing his ambition to reach twelve Books in total. Arthur still becomes an important figure in the epic, with his quest to reach Gloriana forming the backdrop to his interactions with the central knights of each Book, but the latter three Books are more intertwined than are the first three. Book 1 seems to be literarily perfect as a stand-along story, whereas the other books leave an increasing number of unresolved plot threads to be resolved in later sections. Nonetheless, the six books Spenser managed to complete have their own internal consistency and leave nothing for a seventh section to wrap up. Edmund Spenser died before he could complete another book of The Faerie Queene.