"Southern Africa has a long history of intra-regional migration, dating back to the mid-nineteenth century. Migration was probably the single most important factor tying together all of the various colonies and countries of the sub-continent into a single regional labour market during the twentieth century. However, entrenched patterns of migration have undergone major restructuring in the last two decades. Southern Africa is now a region on the move. Several broader changes underlie this shift towards greater and greater intra-regional mobility."