The story of man in the Philippines goes back to the middle of the Ice Ages. In geologic terms this is known as the Pleistocene Epoch which has been dated from 1 to 3 million years. During this period the entire earth underwent great upheavals. At least four times the climate of the world became cold and waters from the oceans were turned to ice and became deposited in the polar regions in the form of glaciers or sheets of ice. During the height of this cold period, the level of the surface of the oceans of the world went down. Huge expanses of land previously covered by water became dry land. Bodies of land separated before by water became connected by dry land bridges. During this period, too, the crust of the earth underwent changes. Pressures from inside the earth and from the various plates of the earth surfaces pushing against one another reshaped forms of land – pushing mountains higher, creating foldings where there were plains, sinking others which were once highlands. For the whole globe, this was a time of tremendous changes. The changes in the land and sea level affected also the climate, the direction and nature of wind and water currents such that plant and animal life were affected to a large degree. It was during this tumultous period when nature appears to have gone on the rampage, that man made his first appearance evident.
The earliest evidence for the presence of people in the Philippine archipelago appeared in Cagayan Valley. These were in the form of stone tools found in the same rock formation as fossils of an extinct elephas. These date back to between .9 to .7 million years or roughly some 750,000 years ago.
Elsewhere in the world as in Indonesia and China the Homo erectus species were dated to at about this age and older. Later population genetics studies suggested that about 50,000 years ago some Proto-malay populations appeared in the country: the Mamanua of Lake Mainit; and between 30,000 to 20,000 years ago the Negrito made their appearance. Evidences point to two streams, one – probably older, is a movement along the eastern side of the archipelago and going farther north along the coast, while the later one coming through Borneo and Palawan affected the western side of the Philippines including Luzon. The Austronesian populations of the archipelago showed their presence between 6,000 to 7,000 years B.C.