Roman Empire/Roman Senate (SPQR) Flag

 

 The Roman Empire is one of the largest empires and civilization's to exist in world history.  It expanded into several parts of three continents, conquering large swaths of land, and governing over millions of people in a little over 500 years.  This flag symbolizes the power of the Roman State and Senate (SPQR) which stands for "Senatus Populusque Romanus" or the Senate and Roman people.