Where does the quote by Tennessee Williams, "A prayer for the wild at heart kept in cages," that Angelina Jolie had tatooed on her forearm come from?

It's the subtitle to a play he wrote: "Stairs To The Roof".

It's a little-known fact that the playwright Tennessee Williams ... the author of "A Streetcar Named Desire" and "Cat on a Hot Tin Roof" ... once worked in a shoe factory in St. Louis. The experience resulted in what was then called a "nervous breakdown." It also resulted in one of his earliest, and most easily forgotten, plays: "Stairs to the Roof". The most memorable part of the play is its subtitle. "A Prayer for the Wild of Heart That are Kept in Cages."

https://en.wikipedia.org/wiki/Stairs_to_the_Roof