Rothko was fascinated by Matisse and called him “the greatest revolutionary in modern art”.
Most of the Pop artists shared this admiration for Matisse but Rothko viewed them as young opportunists and refused to shake hands with Warhol or be in the same room.
In this post of 1964, Rothko shares his painting Homage to Matisse to commemorate the 10th anniversary of Matisse passing.
The quote from Warhol is from an interview of 1962 in Newsweek where he manages to both praise the work and pick on Rothko.
Pop: The Genius of Andy Warhol, Tony Scherman and David Dalton, 2010
Mark Rothko: A Biography, James E. B. Breslin
Mark's homage to Matisse, 2017, Acrylic on canvas, 40" x 30" (102 x 76 cm)