Sophia was the daughter of Richeza of Poland, Dowager Queen of Sweden, from her second marriage to a man called "Valador", King in Poloni Land.

The identity of her father is uncertain, it was either Volodar of Minsk[1] or Vladimir Vsevolodich [ru], Prince of Novgorod and son of Vsevolod of Pskov.

In 1154, at the age of circa fourteen, Sophia was betrothed to Valdemar as a symbol of alliance between Sweden and Denmark: she was at this time described as a pretty girl with promise of becoming a beauty.

[3] Sophia departed Sweden for Denmark after the conclusion of the engagement in 1154, but as she was not yet regarded old enough to marry by Nordic standards, she was sent to reside with a foster mother named Bodil until she was old enough to live with Valdemar.

As queen dowager, Sophia received a proposal from, and married, Louis III, Landgrave of Thuringia in about 1184, and was escorted to the border by her son and a grand entourage.