Official script prevailed in Han dynasty. Wei and Jin Dynasties witnessed the transition from official script to regular script, and two auxiliary characters derived from official script, running script and cursive script, also matured in Wei and Jin Dynasties.
Regular script can indeed be traced back to the Eastern Han Dynasty and prevailed in Sui and Tang Dynasties. Regular script has meticulous strokes, rigorous structure and incomparable practical value, so it is still in use today.
Cursive script originated in the early Han Dynasty and matured in the Eastern Jin Dynasty. Although it is not practical, it has high aesthetic value, and many famous artists come forth in large numbers.