THE tie serves no purpose other than decoration, yet some men take longer to choose a tie than they take to buy a car. It seems there is a need for this adornment. And, historically, there was a reason as it served as a means of identification. According to tailors Robert Talbott, ties go back centuries - neckbands were worn by Roman legionnaires. Louis XIV's Croatian troops wore neck ribbons and the Croats, from whom the French copied the style, were mis-named ''Cravates''. On July 24, 1692, Louis' regiments were surprised by the English at the bloody battle of Steinkirk and, in their haste to get on the field, the generals tied their lace cravats in a knot, rather than taking the time to properly arrange the intricate scarves. And, so, the knotted cravat became fashionable, replacing the neck-high lace collars of Charles I and Charles II. By the 1850s, shorter and smaller cravats, which were then being called neckties, were in vogue. This prompted other changes in masculine dress: collar points were being turned down over the cravat but, in the 1850s, came the real turned-down collar. So, the tying of a knot became varied to accompany the opening provided by various sized collars. Even tying the knot became something of an art form. At this time, too, the ''lounge jacket'' was seen as a shorter, sporty alternative to the frock coat. And the necktie was seen as a fitting accompaniment. As the lounge jacket began to be cut higher and higher in the chest, leaving less exposed shirt front, the necktie became smaller and smaller, until the 1870s when it reached, for all intents and purposes, its modern lines. Popular until well into the 1890s, the longer, narrower tie now had a definite central knot - a ''sailor's knot'' - which had vertical borders, with the ends of the tie flowing down the shirt front, usually about two inches apart. The turn-of-the-century shift to the more formal 'four-in-hand' tie is attributed to Edward VII. This knot was accomplished by wrapping the wider end (the apron) of the tie around the thinner end by pulling it through a self-formed loop; the knot was then pulled tight to the collar. The name was derived from the four-in-hand coach; a slipknot was used to hold the reins of all four horses in one hand. Since then, the only thing which has affected the tie, has been the decreasing size and stiffness of the collar. The starched collar saw its final days when the Prince of Wales appeared in public in the early 1930s wearing a dinner jacket with a soft-collared dinner shirt. So, the modern neck dress - turn-down-collar and four-in-hand tie - has been with us for sometime. In this century, patterns of ties have been diverse: foulards, polka dots, paisleys and regimental stripes. Where did the regimental tie come from? It developed from the concept of wearing identifying badges. The first instance of individual troops being set apart by colour comes with the coronation of James II, which took place on St George's Day, April 23, 1685. It was noted that the three Troops of the Life Guards were distinguished by the colour of the ''large knots of riband in their hats''. From this developed the ''neck ribands'' of the British regiments, the regimental striped tie. When the Prince of Wales visited the United States in 1919, he took the fashion with him and the red and blue striped tie became the rage in America. The fact they were not entitled to wear the ''old school tie'', not being an officer of the Grenadier Guards, was lost on the fashion followers. But while Americans wear it as a mere adornment, rather than a badge of class, those made in the US have stripes which run from the wearer's right down to the left - the reverse of the British style. The reason is that, in Britain, the fabric is cut face up on the cutting table. In the US, it is cut face down.