"ominous tract..."See in text(Childe Roland to the Dark Tower Came)
In this case, the noun “tract” bears multiple meanings. On one level, “tract” refers to the expanse of land to which the old man directs the speaker and which encompasses the Dark Tower. On another level, a tract can refer to a written agreement or pact. By taking the old man’s direction and heading to the tower, the speaker is, in a certain sense, accepting a tract. That the tract is “ominous” foreshadows the dark nature of the journey ahead.
"(See Edgar's song in "Lear")
..."See in text(Childe Roland to the Dark Tower Came)
Browning repeatedly denied any conscious literary influence on this poem other than this nod to Shakespeare’s King Lear, in which Edgar, feigning madness as Poor Tom, sings of his struggles to King Lear in almost nonsensical verse. The torments he describes include a “foul fiend” who leads Poor Tom “through fire and through flame, through ford and whirlipool, o’er bog and quagmire….” This allusion frames the poem not only by foreshadowing the course of the speaker’s journey, but also by casting doubt on the reality of all the events since Edgar’s song is told under the guise of madness.