Anna Sophie was born in Königsberg, the oldest and only surviving child of Duke Albert of Prussia (1490-1568) from his first marriage with Dorothea (1504-1547), a daughter of King Frederick I of Denmark.

She married on 24 February 1555 in Wismar to Duke John Albert I of Mecklenburg (1525-1576).

As a wedding gift, her father mediated in a dispute between her husband and his brother Ulrich, Duke of Mecklenburg.

[2] On the occasion of his marriage, Duke John Albert I had the Fürstenhof Palace in Wismar remodeled in a Renaissance style.

[4] John Albert I remained a loyal ally to his father-in-law, in the Holy Roman Empire as well as in Livonia.