Dr. William Oliver invented this cracker in the mid-1700s for his convalescing patients in Bath, England. He wanted to create a healthy food that went well with the cheeses of the area (cheddar, for one). They've been a mainstay of British cheese trays ever since.
Large, flat and white, they're a "hard-tack" variety of cracker like our Vermont Common crackers. Their flavor reminds me of a southern biscuit. They're suitable for any cheese, but especially nice with longer aged varieties and anything British.