head [OE] English head—in Old English hēafod – has parallels in numerous related languages, including Dutch hoofd and German Haupt. The earlier, more logical, version of head over heels, ‘turning over completely in forward motion’, was heels over head. The modern form dates from the late 17th century. It often describes an extreme condition, as in head over heels in love or head over heels in debt. A variant is head over ears, which is an alteration of earlier, and much more logical, over head and ears [E17th]. The expression to give someone their head [L16th] comes from horse riding. Giving a horse its head meant allowing it to gallop freely rather than checking its pace by using the reins. The same image and meaning is to be found in the phrase to give someone free rein [M17th], which these days people sometimes write as free reign, as if the idea was allowing someone to rule freely.