AI說，伊朗是世界上最悠久的國家，有5千多年曆史，中國排名第六，有四千多年

which country is oldest in the world

Defining the "oldest country in the world" is tricky because it depends on the criteria used

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Based on the earliest evidence of organized government:

• Iran: 3200 BCE.
• Egypt: 3100 BCE.
• Vietnam: 2879 BCE.
• Armenia: 2492 BCE.
• North Korea: 2333 BCE.
• China: 2070 BCE.
• India: 2000 BCE. 

Based on the date of self-sovereignty:

• Japan: 660 BCE.
• China: 221 BCE.
• San Marino: 301 CE.
• France: 843 CE.
• Austria: 976 CE.
• Denmark: Sometime in the 10th century CE.
• Hungary: 1001 CE.
• Portugal: 1143 CE.
• Mongolia: 1206 CE.
• Thailand: 1238 CE.