Pable Picasso was dauntlessly innovative. But even the greats don’t work in isolation. A survey at the Kunstmuseum Basel explores the influence El Greco had on Picasso, showing that their connection was deeper and more enduring than previously understood. In fact, we have El Greco to thank for Picasso and Picasso to thank for rediscovering and preserving the legacy of El Greco. Juxtaposing 30 pairings by the two masters, a rich dialogue emerges. —C.M.