Sweden
Sweden is first described in a written source in Germania by Tacitus in 98 AD. In Germania 44 and 45 he mentions the Swedes (Suiones) as a powerful tribe (distinguished not merely for their arms and men, but for their powerful fleets) with ships that had a prow at each end (longships). Which kings (kuningaz) ruled these Suiones is unknown, but Norse mythology presents a long line of legendary and semi-legendary kings going back to the last centuries BC. As for literacy in Sweden itself, the runic script was in use among the south Scandinavian elite by at least the 2nd century AD, but all that has come down to the present from the Roman Period is curt inscriptions on artefacts, mainly of male names, demonstrating that the people of south Scandinavia spoke Proto-Norse at the time, a language ancestral to Swedish and other North Germanic languages.
The Vikings:
The Kingdom of Sweden:
It is not known when and how the kingdom of Sweden was born, but the list of Swedish monarchs is drawn from the first kings known to have ruled both Svealand (Sweden) and Götaland (Gothia) as one province, beginning with Eric the Victorious. Sweden and Gothia were two separate nations long before that and since antiquity. It is not known how long they existed: the epic poem Beowulf describes semi-legendary Swedish-Geatish wars in the 6th century. Götaland in this sense mainly includes the provinces of Östergötland (East Gothia) and Västergötland (West Gothia). The island of Gotland was disputed by other than Swedes, at this time (Danish, Hanseatic, and Gotland-domestic). Småland was at that time of little interest to anyone due to the deep pine forests, and only the city of Kalmar with its castle was of importance. The south-west parts of the Scandinavian peninsula consisted of three Danish provinces (Scania, Blekinge and Halland). North of Halland, Denmark had a direct border to Norway and its province Bohuslän. But there were Swedish settlements along the southern coastline of Norrland.