SUN'NA (Ar. sunnah, custom, legal usage, tradition, from sanna, to establish a usage or law). In the original meaning among Moslems, the sayings and the example of Mohammed and his community, provided they are in accordance with the Koran, the meaning of which, however, is itself explained by the Sunna. As embracing traditional law, Sunna is divided into three parts: (1) what Mohammed did; (2) what he enjoined; and (3) what was done in his presence and not forbidden by him. The term is therefore (though incorrectly) used for the collections of moral and legal traditions known as Hadith (q.v.) traced to the Prophet, which supplement the Koran, somewhat like the Mishna (q.v.), which supplements the laws of the Pentateuch. The Sunna not only comprises religious doctrines and practice, but also civil and criminal laws, and the usages of common life, the way to eat and to drink, to dress, and the like. For the credibility and canonicity of a tradition, it was originally necessary that it should have been heard by one truthful witness; but this law was much relaxed in later times. By the beginning of the ninth century a large number of individual collections known as Musnads had been produced by different theologians, but the first who sifted them critically, and without regard to any special theological system, was Buchari (810-887). His collection contains 7275 single traditions, 4000 of which, however, occur twice in the work. Muslim. a younger contemporary (817-873), supplemented Buchari with another collection, containing 12,000 traditions, again including 4000 repetitions. Besides these, there are “canonical” collections by Abu Daud (817-888). by Tirmidhi (830-914), a pupil of Buchari, and by Abu Maja (824-886), besides others that also enjoyed some measure of authority. The Sunna, as we have it in these collections, contains, broadly speaking, more truth than it is generally supposed to contain, and, critically used, is, besides the Koran, the most authentic source of a knowledge of Islam. A selection from the different collections (both canonical and otherwise), called Mishkat Al Masabih, has been translated into English by Matthews (Calcutta, 1809). The Arabic text of Buchari has been published by Krehl, Le recueil des traditions musalmanes (Leyden, 1862-68), and fragments of this work in German translation were embodied by Hammer-Purgstall in his Fundgruben des Orients (Vienna, 1810-19). Goldziher has a valuable treatise on the Hadith literature in his Mohammedanische Studien, vol. ii., pp. 1-274 (Halle, 1890).