Henry Louis Gates Jr. is host of the very popular PBS show “Finding Your Roots.” He recently helped make history with a special guest in season 2.

According to the Huffington Post, Nas’ appearance on the show has made him the first rapper to trace his roots on the show. While the rapper was excited to engage in the project, he was also shocked to find a ‘Bill of Sale’ from one of his ancestors who was sold as a slave. The rapper talked about his reaction during a panel discussion about his episode last week.

“First, I was enraged when I looked at the bill of sale,” he said. “I was like, that guy that owned property owes me some cash. My people made him really wealthy, so maybe I should find his family and talk.”

The rapper says he wants to find out more information about his background and believes that it will come into his music on its own.

The upcoming season will also feature Ben Affleck, Angela Bassett, Stephen King and more.

The second season of “Finding Your Roots” is set to air September 23.