On this episode of Dave Does History, we take a royal detour into the wonderfully weird coincidence of two medieval monarchs who shared more than a bloodline—they shared a birthday.

June 13 gave us Charles the Bald and Charles the Fat, two kings from the Carolingian dynasty who ruled over fractured empires with wildly different styles and very different waistlines.

One rebuilt cavalry and outwitted Vikings. The other bought off raiders and watched his empire fall apart. Neither lived up to their nickname, but both lived fascinating, messy lives that remind us just how human history really is.

So grab a goblet, settle into your throne—or your recliner—and let’s explore the story of how two guys named Charles, born sixteen years apart, tried to hold together the ghost of Charlemagne’s empire. It’s birthday cake and battle axes, coming up next on Dave Does History.