Hiero II, also called Hieron II, was the Greek tyrant of Syracuse, Greek Sicily, from 275 to 215 BC, and the illegitimate son of a Syracusan noble, Hierocles, who claimed descent from Gelon. He was a former general of Pyrrhus of Epirus and an important figure of the First Punic War. He figures in the story of famed thinker Archimedes shouting "Eureka".

Syracuse is a historic city on the Italian island of Sicily, the capital of the Italian province of Syracuse. The city is notable for its rich Greek and Roman history, culture, amphitheatres, architecture, and as the birthplace and home of the pre-eminent mathematician and engineer Archimedes. This 2,700-year-old city played a key role in ancient times, when it was one of the major powers of the Mediterranean world. Syracuse is located in the southeast corner of the island of Sicily, next to the Gulf of Syracuse beside the Ionian Sea. It is situated in a drastic rise of land with 2,000 metres (6,600 ft) depths being close to the city offshore although the city itself is generally not so hilly in comparison.