In order to understand what constitutes successful colonization, it is important to understand what colonization means. Colonization refers to large-scale population movements in which the migrants maintain strong links with their or their ancestors' former country, gaining significant advantages over other inhabitants of the territory by such links. When colonization takes place under the protection of clearly colonial political structures, it may most handily be called "settler colonialism". This often involves the settlers' entirely dispossessing earlier inhabitants, or instituting legal and other structures which systematically disadvantage them.