The area in or around Cagayan de Oro was settled as early as 1,600 BC from the Late Neolithic Period to the Metal Age. Evidences of this settlement were discovered in 1970 by field researchers of the National Museum in a cave dwelling and adjacent open site known as the Huluga Caves area, some 8 kilometers south of the present city site. The cave yielded human skeletal remains, pottery, potsherds, tools, and other ornaments. It also yielded glass beads, probably of Indian origin, as well as Chinese pottery fragments, and vestiges of possible Annamese and Thai wares, proof that the people who lived in the site were engaged in trading across the seas. The open site on the other hand, yielded potsherds and Chinese celadon sherds as well as obsidian flakes, volcanic glass used as cutting tools. A skull fragment from the skeletal remains in one of the caves was brought to the Scripps Institute in La Jolla, California for a dating technique known as acid racemization, which process revealed the date of the materials. The Hulugan Caves find is considered as the oldest chronological age ever established in the whole of Mindanao. The Huluga Caves area was pre-historic Cagayan de Oro. The first recorded visit by Spaniards in Cagayan was in the year 1622, when two Augustinian Recollect missionaries first came to the Huluga Caves area, then already known as Himologan. Here they encountered a group of native Filipinos of a mixed stock of Bukidnons and Visayas. The men had a mass of tatoos on their bodies very much like the pintados of the Visayan Islands. The women had intricate jewelries which included those made of gold. These first missionaries were Fray Juan de San Nicolas and Fray Francisco de la Madre de Dios. From the chronicles of these two Recollect friars, we are told when they found the Himologan people, there were no traces of Islamization in the area. In fact, the religious culture was shamanistic and the objects of worship were a polytheistic animism. However, the people paid tributes to Sultan Kudarat through his emissaries from the Lanao area. Sultan Kudarat therefore was able to extract a nominal influence among the Cagayan people. When the Recollect friars arrived in 1622, the area around Himologan was already known as "Cagayan". In fact, early Spanish documents in the 1500s already referred to the place as "Cagayan". The area of Northern Mindanao which included Cagayan, was granted as an encomienda to a certain Juan Griego on January 25, 1571. How did this name originate, when we also known that there is a Cagayan in Lugzon and a Cagayan in Sulu? Language researchers trace the etymology of the name "Cagayan" as coming from the Proto-Philippine language, the root of many Filipino language. In this language, which was Malayo-Polynesian, the word for water was "ag". "Agus" was the "flow of the water" hence "agusan" was "the place where there is a flow of the water". In that same language, "kagay" meant "river". "Kagay-an" meant "the place of the river". That is the root of the name of Cagayan, derived from the great river that runs through the city.