They are a Roman Catholic religious order, and a branch of the Cistercians. The order was founded in 1662 by a converted courtier at La Trappe, in France, hence the name.
Although their order's rules imply observance, and in particular abstinence from alcohol, the monks of several Trappist monasteries make a living in producing liquor. Famous examples are in Belgium, where several Trappist monasteries produce famous trappist beers.
Monasteries include: