At the National Gallery in London, the aging artist who made the pictures in Rembrandt: The Late Works, the most recent blockbuster based on the Dutch master, often seems inward looking. But there’s a barely-visible detail in today’s Daily Pic that makes me think he might have been more engaged, and even political, than that.

The picture, painted in the 1650s and now in Glasgow, is usually thought to show Alexander the Great, the ancient Greek ruler who conquered the Persians and then lands further east. Looking carefully at Alexander’s shield, I thought I could just make out some marks intended to mimic Arabic script. My eyes may have been playing tricks in the glare; the show had tacky stage lighting meant to add sparkle to Rembrandt’s paint. But if I’m right, what I saw would have been the last vestiges of the pseudo-scripts of Renaissance art. Those were eastern-looking letters, aping Hebrew or Arabic or other exotic languages, which for several centuries had been inscribed on such things as the halos of saints and the Virgin Mary’s robes. They pointed to Christianity’s eastern roots in the Roman-held Holy Land, and could signal Europe’s “natural” links to, and maybe rights over, the long-contested terrain there.

In Rembrandt’s time that once-ferocious contest was still simmering, as a fight between a lowering Ottoman Empire and various European nations on its borders. Precisely during the decade when this canvas is supposed to have been painted, the Ottomans were in the middle of one of the longest sieges in military history, of the Venetian city of Candia, on Crete. Since 1648 the tide of battle had turned one way, then another, feeding constant news back to the European heartland. By depicting Alexander as a Christian knight holding a shield with “Arabic” script (a round shield, no less, that would have seemed typically Ottoman) Rembrandt may have been invoking Europe’s eastern conquests of two thousand years earlier, so as to conjure a future where they were repeated.

So much for Rembrandt as a brushman more interested in paint than ideas, or more concerned with achieving “timelessness”–that worst of art-critical clichés–than invested in the moment at hand.