The quote "<em>Cleopatra's nose, had it been shorter, the whole face of the world would have been changed</em>" was said by the famous French mathematician Blaise Pascal. It was part of the posthumously edited writings of Pascal in 1669 titled "Pensees/ Thoughts".
According to the belief of ancient times and also the seventeenth century belief, a person's physiognomy plays an important role in determining the character of that person. A large nose, like that of Cleopatra's, signify the dominance and strength of the person. If not for her, then there wouldn't have been the fall of Caesar or Antony, the great men of Rome. This would have stopped them from falling under her spell, thus averting the many wars and conflicts that changed the history of the world.
Notice how the word soliloquy is a bit like the word 'solo'. This is basically what it is: a solo in drama, where somebody is projecting their inner thoughts. This gives the audience direct access to the character's feelings.
