When the Gunhild-sons had killed Trygve Olafson, king in Viken (the grandson of Harald the Fairhaired), in 963, Trygve's widow Astrid fled with her foster-father, Thorolf Lusarskeg. Astrid was pregnant with a child of King Trygve, and she went to a lake and concealed herself on a small island with a few followers. Here she gave birth to a boy, and she called him Olaf, after his grandfather. She remained there all summer, but when the nights became dark, and the days began to shorten and the weather to be cold, she travelled further with Thorolf and a few others until she reached Ofrustad, where her father, Erik Biodaskalle, lived, and they remained there during the winter. But in the spring spies were sent out by Gunhild to find the boy, and Astrid had to flee again with her son. She proceeded eastward, and at last came to her father's friend, Haakon the Old, in Sweden, where she and her son remained a long time and were well treated. When Gunhild heard that Astrid and her son Olaf were in Sweden, she sent ambassadors to the king of Sweden with the request that the king assist them in getting hold of Olaf Trygvason, to bring him back to Norway, where Gunhild would bring him up. Astrid then determined to go with her son to Gardarike, or Russia, where she had a brother, Sigurd Eriksson, who held a high position there. Olaf was then three years old. As they sailed out into the Baltic, however, they were captured by vikings from Esthonia, who made booty both of the people and their goods, killing some, and taking others as slaves. Thorolf, whom they considered too old for a slave, was killed. Olaf was separated from his mother, and an Esthonian took him and a son of Thorolf as his share of the booty. The boys were sold for a stout and good ram, and a third man, called Reas, afterward bought Olaf for a good cloak. Olaf remained with Reas in Esthonia for six years (967-972), was treated well, and was much beloved by the people. Sigurd Eriksson, the brother of Astrid, happened to come to Esthonia to collect taxes for King Valdemar (or Vladimir), king in Novgorod, Russia. In the market-place he saw a very handsome boy, and as he could see that he was a foreigner, he asked him his name and family. The boy answered that his name was Olaf, that he was a son of Trygve Olafson, and that Astrid, a daughter of Erik Biodaskalle, was his mother. Sigurd thus discovered that the boy was his sister's son, and he bought him, and took him with him to Novgorod, He at first said nothing to the boy about their relationship, but treated him well. Olaf was then nine years old.