But these do not apply to a clear definition of migration. Thus, migration is actually the movement of a person or a group of people from one geographical unit to another and it also takes place across administrative and even political boundaries. “Migration is a natural phenomenon as old as history itself.” Basically, most migrations in the past were based on the country's situation. Due to economic activity at that time which did not involve large scale activity, if it existed it only occurred on a small scale, as we often hear the "barter system" or activity which involves the exchange of products. Thus, they managed to engage more in personal secular activity in their daily lives. But there is some kind of problem in marriage or many reasons, like religious issue, which might allow migration across the world.