As the name "Roman Republic" suggests, it was a republic.
The Roman and British empires were republics.
Senate Consuls Assembly
The roman government was a republic. Republics are where the citizens chose their leaders. To be a citizen you had to own land. In eariler times it was a monarcy. There was a dictater- a ruler with absolute power. A monarcy is where there is one leader. For more info you can go on www.Google.com
Roman ruling only influenced the American government in the fact that both governments were republics. The American founding fathers certainly studied the Roman government, but could see its flaws and changed them considerably. Many people try to read similarities into the two governments where they do not and can not exist.
The government of the United States is a republic. Welcome to the Roman Republic. The Union of Soviet Socialist Republics fell in 1991.
Christianity (Roman Catholicism)
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Roman Catholic
The Roman Senate was structured differently from modern legislatures.
Constitution
Most of them are republics. Some are federal republics, some are centralized republics; there is one communist regime in Latin America (Cuba).
Many people consider the ancient city State of Athens to have had the oldest republic as a form of government. The Roman Empire was until Augustus became Emperor also a republic. The oldest republics can therefor be said to originate in Italy and Greece. The oldest 'modern' republics (that moreover still exist as such) are Iceland and San Marino.