The Saga of Eirik Raude (the Red) gives us a famous descripition of how the the sorcery of seiðr was done. It tells about seiðkona, the sorceress, her clothes and equipment.

She held a staff in her hand, and stones were fasten to her cloak. Her gloves and and cap were lined with cat skin, and there were fasten long straps with brass knobs to her shaggy shoes. She had to sit on a platform.

The song of sorcery was sung by a woman. The woman song beautifully and cleverly. The sorceress thanked her and told her that her song has brought many spirits to the place, and earlier the spirits had not obeyed them. In this way she knew that the bad ear soon will end. -

After being in the service of the Byzantine emperor, Harald Hardråde and his men left Constantinopel heading for the kingdom of Norway in 1045. Harald and his men sailed the Black Sea and reached the mouth of Dnjepr. From there he went to Novgorod (Holmgard) and Aldeigjuborg (Staraya Ladoga), and he reached Norway in 1046.

Snorri tells that Harald Hardråde spent the winter of 1045-46 in Holmgard, and he married Prince Jaroslav's daughter. She was called Eillisiv by the Norwegians and became queen of Norway.

Snorri tells that on these travels in Russia, Harald Hardråde made 16 comic somgs with the same poetic. One of them you can read here in my translation. Harald Hardråde is thinking of Eillisiv in this song.

Room name: Kveda (Norse), verb: to sing esp. folk song with a clear expression of the text; rumr (Norse), noun: room.