Why does Beatrice act as the protector and ultimate guide of Dante toward salvation? What is Beatrice's role?
The character of Beatrice is based on the daughter of a rich Florentine banker, Beatrice Portinari, whom Dante met and fell in love with at the age of nine. Beatrice first appears in the Vita Nuova, a collection of Dante's early poetry, which was put together and commented by the author between 1292 and 1295. That earlier work already introduced Beatrice as "bringer of blessedness", according to the later characterization in The Divine Comedy, since the woman is described as a "nine" (a word that recurs nine time through Vita Nuova), a multiple of "three" and thus a symbol of the Trinity. Beatrice guides Dante through Paradise to the ninth sphere where she entrusts him to St. Bernard who takes him to the Empyrean.
In The Divine Comedy, Beatrice supplies a higher level of knowledge to the pilgrim Dante than that offered by Virgil, who guides him through Hell and Purgatory. The Latin poet represents the highest level of human rationality and reason, but these are not sufficient to understand the Revelation and the Christian Faith which Beatrice represents. The physical love of the Vita Nuova is therefore sublimated in spiritual love in the Divine Comedy and it is out of this love that Beatrice acts to guide Dante toward Salvation. This spiritual function of Beatrice is complemented also by a more didactic one. As Dante's guide, the woman has to teach him and explain the structure of Paradise and Christian theology.