Arrian states that the Persians, in battle, had no bridles, but governed and guided their horses by nose bands, covering sharp pieces of iron, brass, or ivory.

The curb bit, though used in the time of the Roman emperors (in an ancient sculpture Theodosius is represented riding with one of extraordinary leverage), was not adopted by the English until Charles I. in the third year of his reign issued a proclamation, commanding that no person serving in the cavalry should use the snaffle, but in lieu thereof the curb only.

On the frieze of the Temple of Minerva, in the Acropolis of Athens, the horses are represented as ridden (as in the races through the Strada Reale in Malta they are still ridden) without bridles or saddles.

The best bridle for a horse is, of course, that which is best adapted to the particular work he is required to perform.

For racing over turf, where he is required to extend himself like a greyhound, the snaffle-bit only is almost invariably selected.

For cavalry purposes, where he is required suddenly to throw himself on his haunches, wheel to either side, or right about, the curb-bit is added; while by the Turks and those Asiatics who practise their horses to approach a wall at full speed, stop, turn round, and then gallop back again, a curb-bit only is used.

For hunting, both bits are necessary; for while across turf, light soil, and over fences of almost every description, the snaffle is a safer guide than the curb-bit, yet in going through deep ground the latter is absolutely necessary to enable the rider, by holding his horse together, not only to prevent him from extending himself—in which attitude his hind feet would overreach his fore ones before they could be extricated from the sub-soil—but to stop him quickly, for instance to pop through a gap on either side, which he would otherwise override for a considerable distance.

To leap over the hedge of a plantation full of trees on a hot horse, with only a snaffle-bit in his mouth, would be dangerous, and often impracticable; whereas it might easily be effected with a curb-bit, by which the animal could moreover be made to ascend a steep narrow bank, creep along it, and then jump off it, over perhaps the only practicable point in the fence beyond it.

The shape, make, and leverage of bits of all descriptions of course depend on the mouth and disposition of the particular animal for which they are required.

It may, however, be generally stated that for all horses a plain snaffle is better than a twisted one; and that of curb-bits, those are the best which give to the rider the maximum of mechanical power, with, to the noble animal beneath him, the minimum of pain.

To a war horse, as well as to his rider, it may be immaterial whether he be infuriated by spurs pricking his sides, or from the laceration of his mouth by a harsh bit, purposely constructed to hurt him.

As regards a hunter, however, the case is quite different; for while on the one hand his becoming infuriated is dangerous to his master as well as himself, a total absence of pain induces him to give calm attention to the difficult work he has to perform.

Although, therefore, according to the animal's disposition a sufficient amount of leverage is required, the smoother the bit is made the more willing will he be to submit to it, and the less will he be disposed to quarrel with it; indeed this principle has more than once been exemplified by the fact of a run-away horse, over which his rider had apparently no control, stopping gradually of his own accord, in consequence of the rupture of the curb chain, which, having infuriated him by the agony it had inflicted on his lower jaw, had actually caused the very danger it had been created to prevent. And it is for this reason that a leathern strap ought almost invariably to be placed under the hard twisted curb chain, by which simple addition acute pain is removed, without any diminution of strength of the chain or of the leverage of the curb-bit.