Olaf’s rapturous welcome soon began to turn sour. Olaf’s upbringing had made him ruthless even by the standards of a ruthless age. Olaf was still a young child when his father, King Tryggve Olafsson, was murdered, forcing him into exile with his mother. Crossing the Baltic Sea on their way to Russia, their ship was captured by Estonian Vikings and Olaf fell into the hands of a slave dealer called Klerkon. Luckily for Olaf, he was sold to kind-hearted owners who looked after him well as he grew up (Klerkon exchanged him for a good cloak). When Olaf was eight, he was found by his cousin Sigurd who bought his freedom and took him to Novgorod. It was there that the then nine-year-old Olaf ran into Klerkon again and promptly split his head in two with a small axe. As a teenager Olaf became a warrior in Vladimir the Great’s druzhina, but left when he was eighteen to begin a career of Viking raiding. As a man of royal blood, Olaf easily raised a warrior band despite his youth and, as was still the custom, this entitled him to call himself a king. All he needed to do now was to win a kingdom. Eight years of ceaseless raiding in the Baltic and England provided him with the wealth, the reputation and the loyal warrior band to do just that: he was still only about twenty-seven years old.
While Olaf had been in England in 994, he had been baptised by Ælfheah, the archbishop of Canterbury, who was later martyred by the Danes in 1012, and he was determined to break pagan resistance to Christianity once and for all. Olaf was not a patient man and he seems to have concluded from the start that force would bring quicker results than argument. Olaf began his campaign of Christianisation in Viken, where he could count on the support of his father’s family. Olaf treated those who opposed him harshly, killing some, mutilating others, and driving some into exile. Olaf tied practitioners of traditional pagan seiðr magic to rocks by the sea at low tide and left them to drown. The folk of Viken found Olaf’s approach persuasive and by early 997 most had been baptised. That summer Olaf moved to the west of the country, taking a large army with him to quell any opposition. There was none, in part thanks to Olaf’s maternal family, which used its influence in the area to soften up the opposition to Christianity. In the autumn, Olaf moved to the still staunchly pagan Trøndelag and burned the temple at Lade. This was a step too far for the locals and they rose in arms forcing Olaf to withdraw to Viken for the winter. This was only a temporary setback. The following year Olaf returned to the Trøndelag. At first Olaf adopted a conciliatory approach, offering to learn about pagan customs, but this was only to lull his opponents into a false sense of security. At the district thing, Olaf and his men killed the leader of the pagan faction, Járn-Skeggi, in the temple of Thor. Though the pagans had come well-armed, the loss of their leader broke their resistance and they tamely agreed to baptism.
To better consolidate his authority in the all-too independent Trøndelag, Olaf built a palace and a missionary church on a peninsula by the mouth of the Nidelva river, with the river on one side and Trondheim Fjord on the other. As it was almost completely surrounded by water, the site was easy to defend and had good access to sea. It was also only 2 miles from Lade: so closely associated with local independence but now very obviously under royal control. Olaf called the place Kaupangen (‘trading place’), perhaps to attract merchants and the taxes and tolls they could be made to pay, but it soon became known as Nidaros (‘mouth of the Nidelva’). Since the nineteenth century, however, it has been known as Trondheim, now Norway’s third largest city. Olaf also tried to strengthen his authority in the region by marrying Járn-Skeggi’s daughter Gudrun. This turned out to be an almost fatal error of judgment on Olaf’s part: Gudrun did not have a forgiving nature and she tried to stab him to death on their wedding night. After that the saga notes laconically: ‘Gudrun never came into the king’s bed again.’ In spring 999, Olaf completed the conversion of Norway’s coastal districts when he sailed to Halogaland, north of the Arctic Circle, but only after he had defeated the Halogalanders in a sea battle. Around the same time, the Icelandic Althing bowed to Olaf’s pressure and adopted Christianity as the island’s official religion.
Christianisation was only one means by which Olaf hoped to strengthen royal authority. Coinage was an important way that medieval monarchs promoted their image and authority: Olaf opened a mint at Trondheim and issued Norway’s first coinage. He also introduced the office of district governor. However, Olaf’s reign was destined to be a short one. After several years of successful raiding in the Baltic, Erik Håkonarson went to Denmark, where he was welcomed by Svein Forkbeard. In alliance with the Swedish king Olof Skötkonung (r. c. 995 – 1022), who had his own designs on Norwegian territory, the pair began to plot Olaf’s downfall. Their opportunity came in 1000, when Olaf sailed south, through Danish waters, to raid the Wendish lands on the south coast of the Baltic.
According to saga traditions Olaf was goaded into the raid by his new wife Thyre, Svein Forkbeard’s sister. This was no diplomatic marriage: against her brother’s wishes, Thyre had abandoned her pagan husband, a Wendish king, and married Olaf instead. Thyre demanded that Olaf go to Wendland to recover property she had been forced to abandon when she fled from her husband. Against his counsellors’ advice, Olaf is alleged to have agreed. A more plausible scenario is that Olaf believed that a profitable raiding expedition would help heal the wounds of his forced Christianisation and bind the warrior aristocracy in loyalty to him. And as pagans, the Wends were fair game.
Olaf’s expedition went well enough but King Svein’s spies observed his movements closely. As Olaf sailed home that September, Svein and his allies ambushed him at Svöld with a superior force. Svöld has never been identified: some historians favour the German Baltic island of Rügen, others the Øresund, the narrow channel that separates Denmark and Sweden. With sixty-four oars Olaf’s gilded flagship, the drakkar Long Serpent, was one of the largest longships ever built but Olaf had eleven ships, his opponents over seventy and the result was never in doubt.
The exact course of the battle is not known for certain but it probably did not involve individual ship-to-ship actions. Viking Age sea battles were usually fought in much the same way as land battles, but with the ships themselves forming the battlefield. The opposing fleets formed up in line, bows-on to the other. The largest ships were always stationed in the centre. Masts and sails were taken down before battle to clear the decks for action and all manoeuvring was done under oars alone. The defending fleet, as Olaf’s fleet did at Svöld, often used the masts and spars to lash its ships together so that they formed a solid fighting platform on which warriors could move quickly from ship to ship to where they were most needed. The attacking fleet could also do this but only after it had made contact with the enemy. Tactics were simple. The first step was to fasten onto the enemy ships with grappling hooks and anchors, and then board them. Once the deck had been cleared in hand-to-hand fighting, the ship would be cut loose and rowed away. Size was always more important in sea battles than speed and manoeuvrability. The larger a ship was, the more men it carried and the taller it was. A high-sided ship offered better protection from missiles for its crew and it was harder for attackers to board. Its crew could in turn rain missiles down onto the crew of a smaller ship and they were also more easily able to board it.