An English order of knighthood, traceable to the reign of Henry IV., consisting of three classes: the first, Knights Grand Cross; the second, Knights Commanders, and the third, Knights Companions, abbreviated respectively into G.C.B., K.C.B., and C.B.; initiation into the order originally preceded by immersion in a bath, whence the name, in token of the purity required of the members by the laws of chivalry. It was originally a military order, and it is only since 1847 that civil Knights, Knights Commanders, and Companions have been admitted as Knights. The first class, exclusive of royal personages and foreigners, is limited to 102 military and 28 civil; the second, to 102 military and 50 civil; and the third, to 525 military and 200 civil. The motto of the order is Tria juncta in uno (Three united in one); and Henry VI.'s chapel at Westminster is the chapel of the order, with the plates of the Knights on their stalls, and their banners suspended over them.