Earlier this month, Chicago House music legend Frankie Knuckles died at age 59. Over the course of a 30-plus-year career, Knuckles accumulated a diverse and far-reaching fan base. So far-reaching it included a certain couple currently living in the White House. President Barack Obama, in 2004, when he was still a U.S. senator from Illinois, named August 24 Frankie Knuckles Day. Moved by his passing, the Obamas sent a condolence letter to the friends and family of the DJ, which Knuckles’s former collaborator David Morales shared on Facebook. They call him a “trailblazer,” whose “legacy lives on in the city of Chicago and on dance floors across the globe.” Read the letter in full below.