Who was the Hellenistic scientist famous for establishing the value of pi in math?

The tetrarchy system was created under the rule of 

The Battle of Zama ended which Punic War

The major theme(s) of Jesus’ teachings is 

Slaves

Drinking water in the cities of the Middle Ages usually came from wells.

When Gaius Gracchus served as a tribune, 

Muslims regard Muhammad as a Prophet but not as divine.

Land or income given to a vassal in exchange for military service was known as a 

All of the following is true of the ideal of civilized behavior known as chivalry EXCEPT