Daria, I only know about it because I missed the credit to the poet at the end, and really wanted to know who wrote it. So, off to Google. The Library of Congress had received a multitude of requests to know as well, and wrote an interesting blog post chronicling their search. The poem was adapted, so simply searching the words wasn’t enough. I guess a lot of people missed the tiny little tag in the credits, giving credit to the adapted works of the poet! It was a very informative read, as it detailed how they go about finding things and how many requests they receive. Most people attribute it to Rumi, as it definitely sounds like something he would have written.