Servius Tullius ruled Rome from 578 to 534 B.C. under the period of Roman Kingship early in Rome's history. He was a man of plebian birth who married into the royal family then seized the throne. A number of the early laws and customs of Rome are attributed to him and were used to build the Roman Empire. He is, however, a legendary figure and it is possible the reforms attributed to him were actually instituted a century later during the early Roman Republic.
Encyclopedia of Military History, Dupuy & Dupuy, 1979