The Balearic Islands were first colonised by humans during the 3rd millennium BC, around 2,500-2,300 BC from the Iberian Peninsula or southern France, by people associated with the Bell Beaker culture.

Little is recorded on the inhabitants of the islands during classical antiquity, though many legends exist. The story, preserved by Lycophron, that certain shipwrecked Greek Boeotians were cast nude on the islands, was evidently invented to account for the name Gymnesiae (Ancient Greek: Γυμνήσιαι). In addition, Diodorus Siculus writes that the Greeks called the islands Gymnesiae because the inhabitants were naked (γυμνοί) during the summertime. Also, a tradition holds that the islands were colonized by Rhodes after the Trojan War.

The islands had a very mixed population. Several stories describing them as having unusual habits. Some have it that they went naked year-round (a folk etymology claims this inspired the islands’ name), some say they went naked only in the summer, some that they wore only sheepskins—until the Phoenicians arrived and provided them with broad-bordered tunics.

Other stories have it that the inhabitants lived in hollow rocks and artificial caves, that their men were remarkable for their love of women and would trade three or four men to ransom one woman, that they had no gold or silver coin, and forbade the importation of the precious metals—-so that those of them who served as mercenaries took their pay in wine and women instead of money. The Roman Diodorus Siculus described their marriage and funeral customs (v. 18 book 6 chapter 5), noting that Roman observers found those customs peculiar.

In ancient times, the islanders of the Gymnesian Islands (Illes Gimnèsies) constructed talayots and were famous for their skill with the sling. As slingers, they served as mercenaries, first under the Carthaginians, and afterwards under the Romans. They went into battle ungirt, with only a small buckler, and a javelin burnt at the end, and in some cases tipped with a small iron point; but their effective weapons were their slings, of which each man carried three, wound round his head (Strabo p. 168; Eustath.), or, as seen in other sources, one round the head, one round the body, and one in the hand. (Diodorus) The three slings were of different lengths, for stones of different sizes; the largest they hurled with as much force as if it were flung from a catapult; and they seldom missed their mark. To this exercise, they were trained from infancy, in order to earn their livelihood as mercenary soldiers. It is said that the mothers allowed their children to eat bread only when they had struck it off a post with the sling.

The Phoenicians took possession of the islands in very early times; a remarkable trace of their colonisation is preserved in the town of Mago (Maó in Menorca). After the fall of Carthage in 146 BC, the islands seem to have been virtually independent. Notwithstanding their celebrity in war, the people were generally very quiet and inoffensive. The Romans, however, easily found a pretext for charging them with complicity with the Mediterranean pirates, and they were conquered by Q. Caecilius Metellus, thence surnamed Balearicus, in 123 BC. Metellus settled 3,000 Roman and Spanish colonists on the larger island, and founded the cities of Palma and Pollentia. The islands belonged, under the Roman Empire, to the conventus of Carthago Nova (modern Cartagena), in the province of Hispania Tarraconensis, of which province they formed the fourth district, under the government of a praefectus pro legato. An inscription of the time of Nero mentions the PRAEF. PRAE LEGATO INSULAR. BALIARUM. (Orelli, No. 732, who, with Muratori, reads pro for prae.) They were afterwards made a separate province, called Hispania Balearica, probably in the division of the empire under Constantine.

The two largest islands (the Balearic Islands, in their historical sense) had numerous excellent harbours, though rocky at their mouth, and requiring care in entering them (Strabo, Eustath.; Port Mahon is one of the finest harbours in the world). Both were extremely fertile in all produce, except wine and olive oil. They were celebrated for their cattle, especially for the mules of the lesser island; they had an immense number of rabbits, and were free from all venomous reptiles. Amongst the snails valued by the Romans as a diet was a species from the Balearic isles called cavaticae because they were bred in caves. Their chief mineral product was the red earth, called sinope, which was used by painters. Their resin and pitch are mentioned by Dioscorides. The population of the two islands is stated by Diodorus at 30,000.

The part of the Mediterranean east of Spain, around the Balearic Isles, was called Mare Balearicum, or Sinus Balearicus.