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1.Caravaggio
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Born Michele Angelo Merigi (or Amerighi), he took the name Caravaggio from the town where he is presumed to have grown up.
2.Caligula
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Born Gaius Julius Caesar, he was given the nickname Caligula (which means "little (soldier's) boot) by his father's soldiers when he was two or three. This occurred when he joined his father on campaigns in the north of Germania; the soldiers were amused by the fact that he was dressed in a miniature soldier's outfit. Although the name was meant to be affectionate, Gaius reportedly grew to dislike it.
3.Socrates
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4.Tamer[lane]
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His real name was Timur, with the name Tamerlane (or Timur the Lame) given to him by Europeans, referring to his injuries.
5.Pachacuti
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6.Ferdinand [Magellan]
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7.[Buzz] Aldrin
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Born Edwin Eugene Aldrin Jr., he acquired the nickname due to the fact that one of his sisters mispronounced "brother" as "buzzer", which was then shortened to "Buzz". It became his legal first name in 1988.
8.Ashoka
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9.[Nelson] Mandela
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His birth name was Rolihlahla Mandela, but he was given the name "Nelson" by his teacher at the local Methodist school he attended.
10.Hokusai
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11.Butch Cassidy
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His birth name was Robert LeRoy Parker. He acquired the name "Butch" after working as an apprentice to a butcher, and took the name "Cassidy" in honour of his friend Mike Cassidy, a cattle thief.
12.Kǒng [Fūzǐ] (Confucius)
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"Kǒng Fūzǐ" (from which we get the name "Confucius") means "Master Kǒng". His birth name was "Kǒng Qiū".
13.Friedrich [Nietzsche]
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14.[Ronald] Reagan
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15.[Mahatma] Gandhi
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It is a Sanskrit honorific that means "Great Soul".