Answer:
The first century.
Explanation:
2001-2101 is the 21st century ( 100 years) so years 1-101 are in the 1st century.
Hope this helps!
Im pretty sure they used the sun and the stars.
The League of Nations was the international organization set up by Woodrow Wilson in the following days after WWI, and was designed to bring the countries together and stop another world war. However, because of arguments between nations, the League did not last as intended, and was replaced after the second world war by the United Nations, which lasts until today.
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