Sprouts were believed to have been cultivated in Italy in Roman times, and possibly as early as the 1200s in Belgium. The modern Brussels sprout that we are familiar with was first cultivated in large quantities in Belgium (hence the name "Brussels" sprouts) as early as 1587.
Brussels sprouts are related to other better-known vegetables in the Brassica genus like broccoli, cabbage and cauliflower. They are part of the cruciferae or mustard family, so known because of a four-part flower in the shape of a cross.
Typically eaten around Christmas time they are great roasted, stir fried and used up in bubble and squeak.