Ghost character that when Shakespeare dramatised the poem and expanded Mercutio's role, he introduced a brother for him in order to suggest a more fraternal character. Shakespeare appears to be the first dramatist to have used the name Valentine prior to "Romeo and Juliet", but he himself had actually used the name previously. In "Two Gentlemen of Verona", a play about two brothers and also set in Verona, Valentine is a true and constant lover and Proteus is a fickle one. While not primarily based on it, "Two Gentlemen of Verona" adapts several incidents from Brooke's poem, and in all these instances
Proteus shape-changing, has much in common with the central but elusive figure of alchemy, Mercurius. The poet John Milton, aware of the association of Proteus with the Hermetic art of alchemy, wrote in "Paradise Lost" of alchemists who sought the philosopher's stone: In his 1658 discourse "The Garden of Cyrus", Sir Thomas Browne, pursuing the figure of the quincunx, queried: "Why Proteus in Homer the Symbole of the first matter, before he settled himself in the midst of his Sea-Monsters, doth place them out by fives?" Shakespeare uses the image of Proteus to establish the character of his great royal villain