The National Gallery of Art’s Center for Advanced Study in the Visual Arts has appointed Aden Kumler of Universität Basel to deliver the 75th A. W. Mellon Lectures in the Fine Arts. The four-part series, titled "In Praise of Difficulty: Ambiguity, Aesthetics, and the Work of Art in Medieval Europe," will take place in Washington, D.C., from May 3 to May 24, 2026. Kumler's research will examine difficulty and ambiguity as aesthetic strategies in medieval European art, challenging traditional associations of the period with clarity and transcendence.