The 23rd letter of the modern English alphabet, is an addition to the ancient Roman alphabet, having originated from a ligatured doubling of the Roman letter represented by the U and V of modern alphabets. When, in the 7th c., the Latin alphabet was first applied to the writing of English, it became necessary to provide a symbol for the sound (w), which did not exist in contemporary Latin. This sound, a gutturally-modified bilabial voiced spirant, is accoustically almost identical with the devocalized (u), which the sound originally expressed by the Roman U or V as a consonant-symbol; but before the 7th c. this Latin sound had developed into (v). The single u or v therefore could not without ambiguity be used to represent (w), though this was occasionally done, and in some Northumbrian texts was the regular practice. The ordinary sign for (w) was at first uu, but in the 8th c. this began to be superseded by , a character borrowed from the Runic alphabet, in which its name was wyn (Kentish wen). Eventually, the use of became almost universal, but in the mean time the uu was carried from England to the contnent, being used for the sound (w) in German dialects, and in French proper names and ether words of Teutonic and Celtic origin. In the 11th c. the ligatured form was introduced into England by Norman scribes, and gradually took the place of , which finally went out of use about A.D. 1300. The character was probably very early regarded as a single letter, although it has never lost Its orignal name of 'double U'. (Oxford English Dictionary).