At some moment a few years after Jesus Christ died but before the second century began, someone made a brick on the island that would become the cornerstone of Great Britain. The area was controlled by Rome then, and known as Britannia  and as the brick lay green, awaiting the kiln, a cat walked across the wet clay and left its footprints before wandering off to do something else. The clay was fired, the prints fixed, and the brick itself presumably became a piece of a building or road.

Two thousand years later, a Sonoma State master's student named Kristin Converse was poking around the holdings of the Fort Vancouver National Historic Site in Washington state. She was writing her thesis on the business and technology of brickmaking in Portlandia (known more formally as the Willamette Valley). A brick caught her eye. It was part of an odd group that was not of local origin. In one corner, there were the footprints of a cat. Where had this cat lived? 

Back in 1982, the bricks in question had been examined by an archaeologist named Karl Gurcke who specializes in the identification of bricks. "The only bricks that come near to matching this type in size are the so-called 'Roman' bricks," Gurcke wrote in a report on excavations at Fort Vancouver. This suggested that the "type may indeed be Roman in origin," and that they were "shipped over from England."...