Passing from the sign to the material figures of the cross, a very usual classification distinguishes three main forms: (1) the _crux immissa_, or _capitata_ [Latin cross] (fig. 3) known also as the Latin cross, or if each limb is of the same length, + (fig. 4) as the Greek cross; (2) the _crux decussata_, formed like the letter ×, and (3) the _crux commissa_ or tau cross, already mentioned. It was on a crux immissa that Christ is believed to have been crucified. The _crux decussata_ is known as St Andrew's cross, from the tradition that St Andrew was put to death on a cross of that form. The _crux commissa_ is often called St Anthony's cross, probably only because it resembles the crutch with which the great hermit is generally depicted.
The cross in one form or other appears, appropriately, on the flags and ensigns of many Christian countries. The English cross of St George is a plain red cross on a white ground, the Scottish cross of St Andrew is a plain diagonal white cross on a blue ground, and the Irish cross of St Patrick is a plain diagonal red cross on a white ground. These three crosses are combined in the Union Jack (see FLAG).
The cross has also been adopted by many orders of knighthood. Perhaps the best known of these is the cross of the knights of Malta. It is a white cross of eight points on a black ground (fig. 5) and is the proper Maltese cross, a name which is often wrongly applied to the cross _patée_ (fig. 6). The knights of the Garter use the cross of St George, as do those of the order of St Michael and St George, the knights of the Thistle use St Andrew's cross, and those of St Patrick the cross of St Patrick charged with a shamrock leaf. The cross of the Danish order of the Dannebrog (fig. 7) affords a good example of this use of the cross. It is in form a white cross patée, superimposed upon a red one of the same form, and is surmounted by the royal cipher and crown, and has upon its surface the royal cipher repeated, and the legend, or motto, "_Gud og Kongen_" = "God and the King." (For crosses of monastic orders see COSTUME.)
Akin to the crosses of knightly orders are those which figure as charges on coats of arms. The science of heraldry evolved a wonderful variety of cross-forms during the period it held sway in the middle ages. The different forms of cross used in heraldry are, in fact, so numerous that it is only the larger works on that subject which attempt to record them all. For such crosses see HERALDRY.