Portugal, officially the Portuguese Republic, is a country in southwestern Europe, on the Iberian Peninsula. Being the westernmost country of mainland Europe, Portugal is bordered by the Atlantic Ocean to the west and south and by Spain to the north and east. The Atlantic archipelagos of the Azores and Madeira are also part of Portugal. The land within the borders of today's Portuguese Republic has been constantly settled since prehistoric times. Some of the earliest civilizations include Celtic societies, followed by incorporation into the Roman Republic dominions in the 2nd century BC, and subsequently into Germanic Kingdoms, such as the Suebi and the Visigoths, from the 5th to the 8th century. The Moors occupied most of the Iberian Peninsula from the early 8th century when they first arrived and conquered the Christian Kingdoms of Germanic background. After the starting of the Reconquista, in the early 1100s Portugal appeared as a kingdom independent of its Christian neighbors, Castile and Leon. In little over a century Portugal had nearly established its modern-day borders by conquering territory from the Muslim Moors.