Regular script has been attributed to Zhong Yao, of the Eastern Han to Cao Wei period (c. 151–230 AD), who has been called the "father of regular script". However, some scholars postulate that one person alone could not have developed a new script which was universally adopted, but could only have been a contributor to its gradual formation. The earliest surviving pieces written in regular script are copies of Yao's works, including at least one copied by Wang Xizhi. This new script, which is the dominant modern Chinese script, developed out of a neatly written form of early semi-cursive, with addition of the pause (頓/顿 dùn) technique to end horizontal strokes, plus heavy tails on strokes which are written to the downward-right diagonal. Thus, early regular script emerged from a neat, formal form of semi-cursive, which had itself emerged from neo-clerical (a simplified, convenient form of clerical script). It then matured further in the Eastern Jin dynasty in the hands of the "Sage of Calligraphy", Wang Xizhi, and his son Wang Xianzhi. It was not, however, in widespread use at that time, and most writers continued using neo-clerical, or a somewhat semi-cursive form of it, for daily writing, while the conservative bafen clerical script remained in use on some stelae, alongside some semi-cursive, but primarily neo-clerical.