The plum originally came from China via the silk route and became established all around the Mediterranean through the influence of the Greeks and Romans. The technique for drying fruit dates back to the same period. The prune, the result of drying a plum, was known to Greek, Roman and Arab doctors several centuries before the Christian era.
Agen Prunes (pruneaux d'Agen) are named after the port and market town Argen upriver to the Lot and Garonne valleys where the plum trees grow. In the 13th century after the return of the Third Crusade the monks of the Benedictine Abbey of Clairac, near Agen, crossed local plum trees with Damascus plums brought back from Syria, producing a new variety of plum called "Prunier d'Ente" (from the old French word "enter," meaning "to graft.") The Clairac monks were also the first to realise that the fruit could be preserved for an entire year once they had been dried in the sun.
In the past, the plums were first left outdoors on trays or straw and then dried in bread ovens or special kilns, remains of which are sometimes found on farms in the Lot-et-Garonne. The prunes grew popular in the 19th century with the development of merchant shipping, since they were greatly appreciated by sailors making long journeys through Northern Europe. They were stocked as provisions on board ship for their taste and nutritional qualities.
In 2002 the European Union officially recognized the Agen prune, granting it a protected geographical designation. Today there is considerable production of Ente plums, the only variety that can be used to make prunes entitled to the "Agen" designation. Agen Prunes go well with game and can be wrapped in streaky bacon (see Devils on Horseback). They can be steeped in a little Armagnac, wine, water, tea or even coffee before cooking and are used in numerous sweet dishes. They are stewed in red wine for a prune compote, stuffed with marzipan or orange and covered in chocolate to make sweets.
Here is a recipe with a different take on Devils on Horseback:
Stuffed Walnut Agen Prunes
12 large prunes,
12 walnut halves,
12 slices of bacon.
With a small pointed knife, cut the prunes lengthwise and stone them. Place a walnut half in the prune, close it and roll a thin slice of bacon around it. Before serving, place in a hot oven for 5 minutes