Small layers

The books of the classes are from the curricula of historical research that Muslim historians invented early and class, language: collected by classes from the source, whose applied, whose meanings are more likely to be similar to two things if one of them is placed on the other. And the classes of people are their ranks and the class was said twenty years, and the class is sometimes intended in the joint group in the Sheikh's meeting, or the sons of one generation, one era or one class, and they took care of them and wrote important books in it. The class is a convention: an Islamic division, which is the oldest time division that was found in Islamic historical thought.