When Spanish explorers arrived in what is now Costa Rica at the dawn of the 16th century, they found the region populated by several poorly organized, autonomous tribes living relatively prosperously, if wanton at war, in a land of lush abundance. In all, there were probably no more than 200,000 indigenous people on September 18, 1502, when Columbus put ashore near current-day Puerto Limón. Although human habitation can be traced back at least 10,000 years, the region had remained a sparsely populated backwater separating the two areas of high civilization: Mesoamerica and the Andes. Though these tribes were advanced in ceramics, metalwork, and weaving, there are few signs of large complex communities, little monumental stone architecture lying half-buried in the luxurious undergrowth, and no planned ceremonial centers of comparable significance to those located elsewhere in the isthmus.

The region was a potpourri of distinct cultures divided into chiefdoms. In the east along the Caribbean seaboard and along the southern Pacific shores, the peoples shared distinctly South American cultural traits. These groups—the Caribs on the Caribbean and the Borucas, Chibchas, and Diquis in the southwest—were semi-nomadic hunters and anglers who raised yucca, squash, pejibaye (bright orange palm fruits), and tubers supplemented by crustaceans, shrimp, lobster, and game. They chewed coca and lived in communal village huts surrounded by fortified palisades. The matriarchal Chibchas and Diquis had a highly developed slave system and were accomplished goldsmiths. They were also responsible for the perfectly spherical granite balls (bolas) of unknown purpose found in large numbers at burial sites in the Río Térraba valley, Caño Island, and the Golfito region. The people had no written language, and their names are of Spanish origin—bestowed by colonists, often reflecting the names of tribal chiefs.

The most advanced tribes lived in the Central Highlands. The tribes here were the Corobicís, and the Nahuatl, who had recently arrived from Mexico at the time that Columbus stepped ashore. The largest and most significant of Costa Rica’s archaeological sites found to date is here, at Guayabo, on the slopes of Turrialba.

Perhaps more important (little architectural study has been completed) was the Nicoya Peninsula in northwest Costa Rica. In late prehistoric times, trade in pottery from the Nicoya Peninsula brought this area into the Mesoamerican cultural sphere, and a culture developed among the Chorotegas that in many ways resembled the more advanced cultures farther north. The Chorotegas were heavily influenced by the Olmec culture and may have even originated in southern Mexico before settling in Nicoya early in the 14th century (their name means Fleeing People). They developed towns with central plazas; brought with them an accomplished agricultural system based on beans, corn, squash, and gourds; had a calendar; wrote books on deerskin parchment; and produced highly developed ceramics and stylized jade figures depicting animals, humanlike effigies, and men and women with oversized genitals, often making the most of their sexual apparati. Like the Olmecs, they filed their teeth; like the Mayans and Aztecs, the militaristic Chorotegas kept slaves and maintained a rigid class hierarchy dominated by high priests and nobles. Human sacrifice was a cultural mainstay. Little is known of their belief system, though the potency and ubiquity of phallic imagery hints at a fertility-rite religion. Shamans, too, were an important part of each tribal political system.

Alas, the pre-Columbian cultures were quickly choked by the stern hand of gold-thirsty colonial rule—and condemned, too, that Jehovah might triumph over local idols.