Seven virtues
The "Catechism of the Catholic Church" defines virtue as "a habitual and firm disposition to do the good." Traditionally, the seven Christian virtues or heavenly virtues combine the four classical cardinal virtues of prudence, justice, temperance and courage (or fortitude) with the three theological virtues of faith, hope and charity. These were adopted by the Church Fathers as the seven virtues.
The Faerie Queene
In addition to the six virtues Holiness, Temperance, Chastity, Friendship, Justice, and Courtesy, the Letter to Raleigh suggests that Arthur represents the virtue of Magnificence, which ("according to Aristotle and the rest") is "the perfection of all the rest, and containeth in it them all"; and that the Faerie Queene herself represents Glory (hence her name, Gloriana). The unfinished seventh book (the Cantos of Mutability) appears to have represented the virtue of "constancy."