People often think of migration as a recent phenomenon. However, migration has been a feature of human existence for centuries. Humans have always migrated in groups and as individuals to seek freedom from war and conflict, to escape hunger and poverty, to find new economic opportunities and employment, to flee from religious intolerance or political repression, or even to trade and to travel to new places. The historian Robin Cohen (1995) has identified some distinct migration periods or events that have taken place over the last four centuries.