Resentment against Germanic chieftains achieving high rank in the Roman military and factionalism among Roman leaders were among the causes of the period's considerable instability.
The Portuguese Vasco da Gama's Voyage around southern Africa to India took place at the end of the fifteenth century, and by 1502 the trans-Abrabian caravan route had been cut off by political unrest.
One of these urges had to do with creating a state of peace in the midst of turbulence, a "still point of the turning world," to borrow a phrase from T. S. Eliot.
As the century turns, migration, with its inevitable economic and political turmoil, has been called "one of the greatest challenges of the coming century".
There is, first, the New York of the man or woman who was born here, who takes the city for granted and accepts its size and its turbulence as natural and inevitable.