The Ertebølle culture (ca 5300 BC-3950 BC) is the name of a hunter-gatherer and fisher culture dating to the end of the Mesolithic period. It was followed by the Funnelbeaker culture (4000–2700 BC) a culture that originated in southern parts of Europe and slowly advanced up through today's Uppland. Tribes along the coasts of Svealand, Götaland, Åland, north-eastern Denmark and southern Norway learnt new technologies that became the Pitted Ware culture (3200 BC to 2300 BC).
Around 2800 BC, metal was introduced in Scandinavia in the Corded Ware culture. In much of Scandinavia, a Battle Axe culture became prominent, known from some 3,000 graves. The period 2500 BC–500 BC also left many visible remains to modern times, namely the many thousands rock carvings (petroglyph) in west Sweden (notably in Tanumshede) and Norway (Alta).
A more advanced culture came with the Nordic Bronze Age (ca 1800 BC – 500 BC). It was followed by the Pre-Roman Iron Age (5th/4th century BC–1st century BC) and the Roman Iron Age (ca 1–400 AD).
The pre-history of Sweden begins at the end of the Pleistocene epoch at the beginning of Holocene epoch, following the last ice age, the Weichselian glaciation. At the end of the ice age, large parts of south and middle Sweden was covered by water.
Parts of Denmark, Scania and the Norwegian coast line were free from ice around 13000 BC, and around 10000 BC the rim of ice was around Dalsland, Västergötland and Östergötland. It wasn't until 7000 BC that all of Svealand and the modern coastal regions of North-eastern Sweden were free of ice, although the land was by then deeply pressed underwater.
In Scandinavia, the time following the ice age begins at circa 9500 BC and is called at first the Yoldia Stage (after the Yoldia Sea, then the Ancylus Stage, after the Ancylus Lake in turn named after Ancylus fluviatilis, a small fresh-watergastropod from this time. By this time, Denmark and Sweden were joined and the "Baltic Sea" of the age was a fresh water lake called the Ancylus Lake. The Ancylus age is followed by formation of the Littorina Sea and the Litorina Stage (named after the Littorina littorea mollusc) at around 6200 BC.
With the first human colonization of this new land (the territory of modern Sweden was largely under water though, and with radically different coastlines) during the Ancylus and Litorina ages begins the Nordic Stone Age. In recent years there have been archaeological finds in caves which strongly suggest human inhabitation of Scandinavia before the Weichsel glaciation, at least 50.000 years ago, presumably by Neanderthals.
During the 6th millennium BC, southern Scandinavia was clad in lush forests of temperate broadleaf and mixed forests. In these forests roamed animals such as aurochs, wisent, moose and red deer. Now, tribes that we call the Kongemose culture lived off these animals. Like their predecessors, they also hunted seals and fished in the rich waters. North of the Kongemose people, lived other hunter-gatherers in most of southern Norway and Sweden, called the Nøstvet and Lihult cultures, descendants of the Fosna and Hensbacka cultures. These cultures still hunted, in the end of the 6th millennium BC when the Kongemose culture was replaced by the Ertebølle culture in the south.
It is not known what language these early Scandinavians spoke. It might have been similar to basque, due to the distribution of the monuments by early megalith builders. Towards the end of the 3rd millennium BC, they were overrun by new tribes who many scholars think spoke Proto-Indo-European, the Battle-Axe culture. This new people advanced up to Uppland and the Oslofjord, and they probably provided the language that was the ancestor of the modern Scandinavian languages. These new tribes were individualistic and clearly patriarchal with the battle axe as a status symbol. They were cattle herders and with them most of southern Scandinavia entered the Neolithic. However, soon a new invention would arrive, that would usher in a time of cultural advance in Scandinavia, the Bronze Age.
During the Nordic Bronze Age, an advanced civilization manufacturing bronze weapons and bronze and gold jewellery appears in Denmark, Sweden and parts of Norway. It has been assumed that this civilization was founded in amber trade, through contacts with Central European and Mediterranean cultures.
The period 2300-500 BC was the most intensive petroglyph carving period, consisting of carvings of an agricultural nature and depicting warfare, ships, domesticated animals, etc. There has also been found petroglyphs with themes of sexual nature in Bohuslän; these are dated from 800-500 BC.
Tacitus (about 98 AD) described a nation called "Suiones" living on an island in Sea. These Suiones had ships that were peculiar because they had a prow in both ends (the shape we recognise as Viking ships). This word Suiones is the same name as Anglo-Saxon Sweon whose country was called Sweoland (Svealand). In Beowulf, this tribe is also called Sweoðeod, from which the name Sweden is derived, and the country has the name Sweorice which is an old Anglo-Saxon form of the present Swedish name for Sweden.
In the 6th century the Ostrogoth Jordanes mentioned a tribe named Suehans which is the same name as Tacitus' Suiones. He also unwittingly described the same tribe by a different name, the Suetidi which is the same as an old name for Sweden, Svíþjóð and the English Sweoðeod.
Several sources, such as Beowulf, Ynglingatal, Ynglinga saga, Saxo Grammaticus and Historia Norwegiae, mention a number of Swedish kings who lived in the 6th century, such as Eadgils, Ohthere and Onela, as well as a number of Geatish kings. Some of these kings were in all likelihood historic kings, although the sources sometimes give contradictory information, such as the death of Ottar. See Mythological kings of Sweden and Semi-legendary kings of Sweden.
In those days the kings were warlords rather than kings as we understand that title today, and what was to become Sweden, Norway and Denmark in a modern sense, were a number of petty kingdoms whose borders changed constantly as the kings killed each other, and had the local assemblies accept them as kings. The politics of these early kingdoms are retold in Beowulf (see e.g. the semi-legendary Swedish-Geatish wars) and the Norse sagas.
One of the most powerful kings was the Swedish king who according to early sources only ruled what is today eastern Svealand. It is unknown when it happened and it probably happened several times, but when sources become more reliable the territories of the Swedish kings include Västergötland and other parts of Götaland. This stage is by some considered to be the beginning of Sweden, as we know it today.