The old text version got its name because it was written in characters not used since the earlier Warring States period (i.e. before 221 BC), when it was assumed to have been hidden. According to the Han dynasty scholar Huan Tan, the old text version had four hundred characters different from the Lu version (from which the received text of the "Analects" is mostly based), and it seriously differed from the Lu version in twenty-seven places. Of these twenty-seven differences, the received text only agrees with the old text version in two places.