Gesta Hammaburgensis ecclesiae pontificum in the context of "Limes Saxoniae"

The term Norwegian Realm (Old Norse: *Noregsveldi, Bokmål: Norgesveldet, Nynorsk: Noregsveldet) and Old Kingdom of Norway refer to the Kingdom of Norway's peak of power in the 13th century after a long period of civil war before 1240. The kingdom was a loosely unified nation including the territory of modern-day Norway, modern-day Swedish territory of Jämtland, Herjedalen, Ranrike (Bohuslän) and Idre and Särna, as well as Norway's overseas possessions which had been settled by Norwegian seafarers for centuries before being annexed or incorporated into the kingdom as 'tax territories'. To the North, Norway also bordered extensive tax territories on the mainland. Norway, whose expansionism starts from the very foundation of the Kingdom in 872, reached the peak of its power in the years between 1240 and 1319.

At the peak of Norwegian expansion before the civil war (1130–1240), Sigurd I led the Norwegian Crusade (1107–1110). The crusaders won battles in Lisbon and the Balearic Islands. In the Siege of Sidon they fought alongside Baldwin I and Ordelafo Faliero, and the siege resulted in an expansion of the Kingdom of Jerusalem. Leif Erikson, an Icelander of Norwegian origin and official hirdman of King Olaf I of Norway, explored America 500 years before Columbus. Adam of Bremen wrote about the new lands in Gesta Hammaburgensis ecclesiae pontificum (1076) when meeting Sweyn I of Denmark, but no other sources indicate that this knowledge went farther into Europe than Bremen, Germany. The Kingdom of Norway was the second European country after England to enforce a unified code of law to be applied for the whole country, called Magnus Lagabøtes landslov (1274).

Harald Sigurdsson (Old Norse: Haraldr Sigurðarson; c. 1015 – 25 September 1066), also known as Harald III of Norway and given the epithet Hardrada in the sagas, was King of Norway from 1046 to 1066. He unsuccessfully claimed the Danish throne until 1064 and the English throne in 1066. Before becoming king, Harald spent 15 years in exile as a mercenary and military commander in Kievan Rus' and chief of the Varangian Guard in the Byzantine Empire. In his chronicle, Adam of Bremen called him the "Thunderbolt of the North".

In 1030, the fifteen-year-old Harald fought in the Battle of Stiklestad alongside his half-brother Olaf Haraldsson. Olaf sought to reclaim the Norwegian throne, which he had lost to Danish king Cnut two years previously. Olaf and Harald were defeated by forces loyal to Cnut, and Harald was forced into exile to Kievan Rus'. Thereafter, he was in the army of Grand Prince Yaroslav the Wise, becoming captain, until he moved on to Constantinople with his companions around 1034. In Constantinople, he rose quickly to become the commander of the Byzantine Varangian Guard, seeing action on the Mediterranean Sea, in Asia Minor, Sicily, possibly in the Holy Land, Bulgaria and in Constantinople itself, where he became involved in the imperial dynastic disputes. Harald amassed wealth whilst in the Byzantine Empire, which he shipped to Yaroslav in Kievan Rus' for safekeeping. In 1042, he left the Byzantine Empire, returning to Kievan Rus' to prepare to reclaim the Norwegian throne. In his absence the Norwegian throne had been restored from the Danes to Olaf's illegitimate son Magnus the Good.

The Polans (Polish: Polanie; Latin: Polani, Polanos), also known as Polanians or Western Polans (Polish: Polanie Zachodni; Latin: Polani Occidentis), were a West Slavic and Lechitic tribe who inhabited the Warta River basin of the contemporary Greater Poland region starting in the 6th century.

They were one of Central Europe's main tribes and closely related to the Vistulans, Masovians, Czechs and Slovaks. According to Zygmunt Gloger, their name was derived from the word "pole", meaning "field", thus denoting them as "men of the fields".

The ethnonyms for the Poles (people) and Poland (their country) include endonyms (the way Polish people refer to themselves and their country) and exonyms (the way other peoples refer to the Poles and their country). Endonyms and most exonyms for Poles and Poland derive from the name of the West Slavic tribe of Polans (Polanie), while in some languages the exonyms for Poland to derive from the name of another tribe – the Lendians (Lędzianie).

Adam of Bremen (Latin: Adamus Bremensis; German: Adam von Bremen; before 1050 – 12 October 1081/1085) was a German medieval chronicler. He lived and worked in the second half of the eleventh century. Adam is most famous for his chronicle Gesta Hammaburgensis ecclesiae pontificum (Deeds of Bishops of the Hamburg Church). He was "one of the foremost historians and early ethnographers of the medieval period".

In his chronicle, he included a chapter mentioning the Norse outpost of Vinland, and was thus the first European to write about the New World.

The Temple at Uppsala was long held to be a religious centre in the Norse religion once located at what became Gamla Uppsala (Swedish "Old Uppsala"), Sweden attested in Adam of Bremen's 11th-century work Gesta Hammaburgensis ecclesiae pontificum and in Heimskringla, written by Snorri Sturluson in the 13th century. Uppsala has for long been exposed to fanciful theories about the implications of these descriptions of the temple and of the findings of archaeological excavations in the area, including findings of extensive wooden structures and log lines from the 5th century which allegedly played a supporting role to activities at the site, including ritual sacrifice. According to sources from the later Middle Ages the temple was destroyed by King Inge the Elder in the 1080s, but there are no contemporary sources to support that.