This poem appears at the end of Marlowe's tragedy Doctor Faustus. At this point in the play, Faustus's time on earth is up and the devils are ready to take him to hell to fulfill the bargain he signed in blood. He now asks Mephistophilis to bring up the image of Helen of Troy, considered the most beautiful woman in the ancient world, and also a figure associated with fire, in this context hellfire. According to Peter Davison (see the eNotes page linked to below) in his commentary "Doctor Faustus" (International Dictionary of Theatre: Plays, edited by Mark Hawkins-Dady) the moment in the poem that Helen kisses Faustus and her “lips suck forth [his] soul," Faustus is finally permanently damned. 

A main theme of the poem is that Faustus, even at the end, continues to focus on the sensual and physical rather than the spiritual, yet again losing his chance for salvation. He still locates his soul in the material world: "heaven is in these [Helen's] lips." He worships Helen in cliched love language: "all is dross that is not Helena." This worship proves to be lust, not love: he tells her "none but thou shalt be my paramour!" He is not allowed to marry, because that is a sacrament and he is in the devil's grasp, but at the same time, his sin of despair leads him not to repent. He chooses to stay in the land of the lustful and sensual, missing the deeper (in this case, Christian) dimension of life.

Another, related theme of the poem is that Faustus can only experience lust, not love. All that attracts him to Helen is her superficial beauty, her outward form. We also see his pride as he shows off his knowledge of Greek mythology. At the moment of his damnation he is, fittingly, talking about pagans, such as the pagan god, Jupiter.

The overarching theme of the poem is to show that Faustus, for all his pride and learning, is still a superficial, shallow being clinging to the physical plane. This distracts him from repentance and salvation, allowing him to be led off to hell.

Obviously an allusion to Helen, "The Face That Launch'd a Thousand Ships" by Christopher Marlowe is a poem about beauty and infatuation more than true love.

Marlowe is using Helen as a concept of beauty, rather than a literal person. He is referring to the power of her beauty, not the owner of it. He talks about how that power would affect him and what he would do because of it. Note that the author never speaks of her individual personality as a human, but he refers to her beauty merely on a physical and worldly level. Clearly, it is not her personality that drives him to act. It is his infatuation with that beauty, but whose beauty it belongs to is irrelevant. As a result, the theme may appear to be love, but it isn't. It's the power of beauty and physical infatuation. As the Greeks say, it is about "eros."