Two Seated Apostles from a Pentecost Scene by http://www.wikidata.org/.well-known/genid/a8192cc720dec92c631e30b58f5d0332

This fragment of a stained glass window, "Two Seated Apostles from a Pentecost Scene" from around 1245, holds a small secret in its lower margin. While the figures themselves are expressive and central to the piece's religious narrative, a closer look at the decorative border reveals more about its creation.

The panel features two haloed apostles, likely part of a larger Pentecost scene. The vibrant blues, reds, and greens of the glass, combined with the bold lines defining the figures, create a luminous effect that has captivated viewers for centuries. The apostle on the left shows surprise, while the one on the right is deep in contemplation.

Look closely at the lower left corner. You'll find a delicate blue floral motif and, just above it, the letters 'NAC'. This inscription is believed to be the signature or workshop mark of Nicholas of Cologne, a master stained-glass maker from the medieval period. This detail offers a direct link to the artisans who crafted such magnificent works of art.

It's incredible to think of the hands that created this nearly 800 years ago, and how such small details can connect us to their story. What other hidden marks might ancient artworks hold?