Between the late Tenth and the mid Thirteenth centuries Portugal emerged as an independent kingdom with borders that have remained largely unchanged until the present day. This political development took place against the backdrop of a struggle between Christendom and the Islamic world for control over the Iberian Peninsula, but also decisive in the formation of Portugal was a growing European influence being felt throughout the peninsula during these centuries. This cultural influence took the form of direct immigration, growing commercial and social networks, and the transfer of ideas and social mores. Portuguese rulers sought to mediate this European influence to their own advantage. In the twelfth century Afonso Henriques (1128-1185) was able to establish the Portuguese monarchy, but his heirs Sancho I (1185-1211), Afonso II (1211-1223) and Sancho II (1223-1245), found the balance between Iberian reality and European expectation increasingly difficult to maintain.