Liu Bang was born in BC256. When he was young, ha gad a great aim -- to become a emperor. After Emperor ShiHuang of Chin Dynasty died, the Chin Dynasty was destroyed, and the society became disturbed. But heroes always appear in the times of anarchy and disorder. Lots of people organized their own army to fight for the rulership, and Liu Bang was one of them. The war lasted for more than seven years.
Finally, Liu Bang wined and founded a new dynasty -- Han.

These words mean: The Original Emperor
Generally, the first emperor of each dynasty was always called "GaoZu","GaoZong","TaiZu","TaiZong", all these words mean the same meaning.