The Roman Republic The political structure: collective and annual magistracies, overseen by a senate. The top magistrates; two consuls, who had an extensive range of executive, legislative, judicial, military, and religious powers. While there were elections each year, the Republic was not a democracy, but an oligarchy, as a small number of powerful families (called gentes) monopolized the main magistracies. The Republic was in a state of quasi-perpetual war throughout its existence. Its first enemies were its Latin and Etruscan neighbours as well as the Gauls, who even sacked the city in 387 BC. After the Gallic Sack, Rome conquered the whole Italian peninsula in a century, which turned the Republic into a major power in the Mediterranean. The Republic's greatest enemy was doubtless Carthage, against which it waged three wars. The Punic general Hannibal famously invaded Italy by crossing the Alps and inflicted on Rome two devastating defeats at Lake Trasimene and Cannae, but the Republic once again recovered and won the war thanks to Scipio Africanus at the Battle of Zama in 202 BC. With Carthage defeated, Rome became the dominant power of the ancient Mediterranean world. It then embarked on a long series of difficult conquests, after having notably defeated Philip V and Perseus of Macedon, Antiochus III of the Seleucid Empire, the Lusitanian Viriathus, the Numidian Jugurtha, the Pontic King Mithridates VI, the Gaul Vercingetorix, and the Egyptian queen Cleopatra. The Roman Republican coinage is the best source of information on the events listed aboe.