Who is Husam Chelebi from The Essential Rumi and what is their importance?

Husam Chelebi was the third and final main companion of Rumi's lifetime. He was actually one of Rumi's students. Husam was also a scribe, thus, he was able to help Rumi in writing down the poetry that emerged. Husam is mentioned in several poems because he was successful as a scribe, student, and intimate personal friend of Rumi's.