When was the 5th book of Faerie Queen written?

Edmund Spenser, a 16th century English poet, published the first three books of The Faerie Queen in 1590. From the onset, this work was a profound tribute to the Queen of England, the nation itself, and the religious values of Protestantism.
After the first three installments in 1590, Spenser focused on a variety of poetry including a full volume, a pastoral, sonnets, and two wedding poems. In 1596, Spenser returned to his masterpiece, and published the final six-book version of The Faerie Queen, which added three more books to the original three books.
Logically, we can conclude that the 5th book of The Faerie Queen was published in 1596, as a part of the final version of the work. The 5th book revolves around the notion of Justice, as exemplified by Sir Artegal.