Little is known of the earliest Stone Age inhabitants of Europe's southwestern extremity. The ancient Greeks called them the Cynetes (or Cunetes). Whatever their origins, their culture evolved under the pressure and influence of foreign forces. Among the many invading armies that settled here and contributed to nascent Portuguese culture were Phoenicians, who settled in the area around 1,000 b.c., followed by the Celts, Iberians, Greeks, and Carthaginians. But it was the Romans, who arrived late in the third century b.c., who most greatly influenced all of Iberia. They built towns, industries, roads, and bridges, developed agriculture, and bequeathed the Latin language, of which Portuguese is a direct descendant. The Romans named the southwestern province of the peninsula Lusitania, oddly enough for one of the Celtiberian tribes they defeated, and by the third century a.d. had introduced Christianity. By the beginning of the fourth century the Algarve had a bishop in place, based in Faro. But Rome had already fallen into decay, and soon hordes of northern tribesmen took over the empire. The Algarve fell to the Visigoths in the mid-fifth century. Under Moorish Rule In a.d. 711, the Moors brought powerful armies from North Africa and launched a devastating attack on the Iberian peninsula, conquering much of what would become Spain and Portugal. They imposed Islam and left an indelible influence on the countryside and the population of the Algarve. The Moorish legacy can still be seen in the form of wells and waterwheels, squat white houses, the dark complexions of the people, and in the very name given the regiontaken from Al-Gharb, which means "country of the west" (when the Moors conquered the territory, it was the most westerly in the known world). The Moors governed their Iberian kingdoms from across the border in Seville, but the Algarve had its own regional capital and huge, invulnerable fortress. The capital was Chelb (or Xelb), and it was bigger and better defended than Lisbon. Today the town, known as Silves, is a provincial outpost whose only besiegers are busloads of tourists who climb the narrow streets up to the old Moorish ramparts.

What did the Greeks call the early Stone Age inhabitants?

So what is gravity? A typical definition of gravity is that it is a force. It causes an attraction between two masses. According to this definition, anything that has mass exerts a force. Any object exerts gravity on other objects. It does not matter how small it is, it has gravity. The more matter an object has, the more gravity it has. Your pencil has a tiny bit of gravity, but far too little to notice. What about a planet? It would have a lot of gravity. An objects gravity exerts a pull on other objects. Friction only occurs between objects that are touching. Gravity can act between objects that are not touching. In fact, gravity can act over very long distances. Where else can you feel gravity?

What does an objects gravity cause it to do?

Though prehistoric remains from the Paleolithic, Neolithic, and Bronze Ages have been unearthed in the Manzanares Valley, prior to Madrid's sudden elevation to capital city in 1561 its history was rather undistinguished. Over a period of many centuries crucial in Spanish history, Madrid's significance was negligible. The Romans built their most advanced outpost on the Iberian peninsula, but left nothing of consequence in Madrid. Armies of North African nomads, intent on disseminating Islam, invaded the peninsula in a.d. Within 10 years, they had overrun most of Spain. If Madrid played any role in these pivotal events, no record of it remains. The first solid references to this obscure settlement on the Castilian plateau, guarded by the looming Guadarrama mountain range, appear in the 9th century. The Arabic name for "place of many springs," variously recorded as Magerit, Mayrit or Magrit, eventually evolved into Madrid. The hamlet entered historical chronicles for its military significance; it was located near the main line of resistance to the Christian reconquest. Over centuries of struggle, the defending Moorish army built a full-scale fort, or Alcazar, on the heights of Madrid commanding the Manzanares valley. After several unsuccessful skirmishes, the Christian forces of Alfonso VI captured Madrid in 1083. The Alcazar became a fort of the crown of Castile. During a counter-offensive in 1109, the town was overrun by the Moors, but the Christianized fortress held. The Moors were expelled from the town, but they remained in control of southern Spain for almost four centuries. Meanwhile, Madrid enjoyed brief prominence in 1308 when king Ferdinand IV and his Cortes, an early version of parliament, held a formal meeting in the fledgling town. From then on, the kings of Spain began to visit Madrid, where the air was invigorating and the hunting excellent. Ferdinand and Isabella, the Catholic monarchs that united all the provinces of Spain, first visited Madrid in 1477.
Why did kings of Spain visit Madrid?