But another type of tradition-book was growing up, less mechanical in arrangement. It is the _Musannaf_, the arranged, classified—and in it the traditions are arranged in chapters according to their subject matter. The first _Musannaf_ to make a permanent mark was the _Sahih_—sound—of al-Bukhari, who died in A.H. 257. It is still extant and is the most respected of all the collections of traditions. The principle of arrangement in it is legal; that is, the traditions are classified in these chapters so as to afford bases for a complete system of jurisprudence. Al-Bukhari was a strong opponent of speculative law and his book was thus a protest against a tendency which, as we shall see later, was strong in his time. Another point in which al-Bukhari made his influence felt and with greater effect, was increased severity in the testing of traditions. He established very strict laws, though of a somewhat mechanical kind, and was most scrupulous in applying them. His book contains about seven thousand traditions, and he chose those, so at least runs the story, out of six hundred thousand which he found in circulation. The rest were rejected _as failing to meet his tests_. How far the forgery of traditions had gone may be seen from the example of Ibn Abi Awja, who was executed in A.H. 155, and who confessed that he had himself put into circulation four thousand that were false. Another and a similar _Sahih_ is that of Muslim, who died in A.H. 261. He was not so markedly juristic as al-Bukhari. His object was rather to purify the mass of existing tradition from illegitimate accretions than to construct a basis for a complete law code. He has prefixed a valuable introduction on the science of tradition generally. In some slight details his principle of criticism differed from that of al-Bukhari. These two collections, called the two _Sahihs—as-Sahihan_—are technically _jami‘s, i.e._ they contain all the different classes of traditions, historical, ethical, dogmatic and legal. They have also come to be, by common agreement, the two most honored authorities in the Muslim world. A believer finds it hard, if not impossible, to reject a tradition that is found in both. [Sidenote: THE SUNAN] But there are four other collections which are called _Sunan_—Usages—and which stand only second to the two _Sahihs_. These are by Ibn Maja (d. 303), Abu Da’ud as-Sijistani (d. 275), at-Tirmidhi (d. 279) and an-Nasa’i (d. 303). They deal almost entirely with legal traditions, those that tell what is permitted and what is forbidden, and do not convey information on religious and theological subjects. They are also much more lenient in their criticisms of dubious traditions. To work exclusion with them, the rejection needed to be tolerably unanimous. This was required by their stand-point and endeavor, which was to find a basis for all the minutest developments and details of jurisprudence, civil and religious.