Dante Alighieri, the author of Dante's Inferno, includes as Dante's (the character) guide Publius Vergilius Maro (or Virgil). Dante (the character) comes upon Virgil (the character) during his journey to find the the sunlight (which he spots over a mountain). Dante comes across different animals until he comes to a place where he cannot pass. Virgil enters and tells Dante that he can show him a different path (one where Dante can see departed souls), Dante agrees to follow Virgil. In this aspect, Virgil acts as Dante's guide. Virgil also symbolizes reason.
As for the man Virgil, his works influenced the works of many others. Virgil's impact on Dante (the poet) is evident given Dante's inclusion of Virgil as his guide. Dante, then, obviously looked to Virgil as a mentor (even though he had passed long before Dante's lifetime). Dante's use of the epic further proves Virgil's influence.
That said, although Dante (the character) accepted Virgil (the Character)--noted by his "father/son" relationship noted in the Inferno, Dante (in life) condemned Virgil given he believed him to be a sodomite.