Vikings were a seafaring people originally from Scandinavia (present-day Denmark, Norway, and Sweden), who from the late 8th to the late 11th centuries raided, pirated, traded, and settled throughout parts of Europe. They voyaged as far as the Mediterranean, North Africa, the Middle East, Greenland, and Vinland (present-day Newfoundland in Canada, North America). In their countries of origin, and in some of the countries they raided and settled, this period of activity is popularly known as the Viking Age, and the term "Viking" also commonly includes the inhabitants of the Scandinavian homelands as a whole during the late 8th to the mid-11th centuries. The Vikings had a profound impact on the early medieval history of northern and Eastern Europe, including the political and social development of England (and the English language) and parts of France, and established the embryo of Russia in Kievan Rus'.

Expert sailors and navigators of their characteristic longships, Vikings established Norse settlements and governments in the British Isles, the Faroe Islands, Iceland, Greenland, Normandy, and the Baltic coast, as well as along the Dnieper and Volga trade routes across Eastern Europe where they were also known as Varangians. The Normans, Norse-Gaels, Rus, Faroese, and Icelanders emerged from these Norse colonies. At one point, a group of Rus Vikings went so far south that, after briefly being bodyguards for the Byzantine emperor, they attacked the Byzantine city of Constantinople. Vikings also voyaged to the Caspian Sea and Arabia. They were the first Europeans to reach North America, briefly settling in Newfoundland (Vinland). While spreading Norse culture to foreign lands, they simultaneously brought home slaves, concubines, and foreign cultural influences to Scandinavia, influencing the genetic and historical development of both.

Roskilde ( ROSK-il-ə, Danish: [ˈʁʌskilə]) is a city 30 km (19 mi) west of Copenhagen on the Danish island of Zealand. With a population of 53,354 (as of 1 January 2025), the city is a business and educational centre for the region and the 10th largest city in Denmark. It is governed by the administrative council of Roskilde Municipality.

Roskilde has a long history, dating from the pre-Christian Viking Age. Its UNESCO-listed Gothic cathedral, now housing 39 tombs of the Danish monarchs, was completed in 1275, becoming a focus of religious influence until the Reformation. With the development of the rail network in the 19th century, Roskilde became an important hub for traffic with Copenhagen, and by the end of the century, there were tobacco factories, iron foundries and machine shops. Among the largest private sector employers today are the IT firm BEC (Bankernes EDB Central) and seed company DLF. The Risø research facility is also becoming a major employer, extending interest in sustainable energy to the clean technology sphere. The local university, founded in 1972, the historic Cathedral School, and the Danish Meat Trade College, established in 1964, are educational institutions of note. Roskilde has a large local hospital which has been expanded and modernized since it was opened in 1855. It is now increasingly active in the research sphere.