The poem to which you actually refer is Blake’s “How Sweet I Roam’d from Field to Field,” which contains within it a line that refers to the “Prince of Love.”
How sweet I roam'd from field to field,
And tasted all the summer's pride,
'Till I the prince of love beheld,
Who in the sunny beams did glide!
The poem in short tells the story of the temptation and subsequent betrayal of love. In its first two stanzas, the speaker narrates her discovery of a seemingly loving prince. He gives her roses and lilies to put in her hair; he shows her his beautiful gardens. It seems like nothing maleficent could grow in such a place.
However, in the second half of the poem an evil turn unfolds. This is where the speaker begins her comparison of herself to a caged bird. The “May dew,” which sounds so benign, wets the speaker’s wings, effectively grounding her and rendering her unable to escape. While Phoebus (the sun) lit within her a “vocal rage,” the speaker says of the prince,
He caught me in his silken net,
And shut me in his golden cage.
In these lines, Blake creates contrast as he assigns items of beauty with a menacing purpose. The prince of love is obviously not the person the speaker believed him to be.
In the fourth and final stanza, we see that the speaker is thus held in captivity for the amusement of the prince. While she entertains him, he laughs and taunts her, even “mocks [her] loss of liberty.” The woman who once had all the freedom to roam wherever she pleased is now jailed by the man she thought “the prince of love.”
So, that’s the summary of the poem’s events. As for its meaning, we can take the poem in a couple of directions:
- The prince can be taken as a literal character who seduces and exploits a naïve girl.
- Alternatively, the prince of love could be a symbol of the god of love, Cupid. Since a mythological reference to Phoebus (Apollo, god of the sun) is written in the poem, such a conclusion would not be a drastic leap. The poem could then signify the betrayal of love itself, as opposed to the betrayal of one person by another.
Ultimately, Blake’s sweet-sounding but sinister poem speaks to the theme that “all that glitters is not gold”; that which may appear tempting and sweet on its surface may hide an evil intent. Blake even embodies this theme in the style of "How Sweet I Roam'd," via its sing-song cadence and abab cdcd rhyme scheme--a style that lies in sharp juxtaposition with the poem's unsettling sequence of events. "How Sweet I Roam's from Field to Field" therefore speaks to any situation in which one has been drawn in and exploited by that which once appeared too good to be true.
I recommend perusing the biography of William Blake below to discover more on his views of love and sexuality, which would further aid in the analysis of this interesting poem.