Merseburg acquired importance beyond the immediate region in the 10th century when it came to King Heinrich I (Henry I) by marriage. He built a Kaiserpfalz there overlooking the Saale and founded a church next to it, consecrated in 919. His son and successor, Otto I swore an oath on 10 August 955 to establish a diocese at Merseburg if God would grant him victory at the upcoming Battle of Lechfeld. In 968, the Diocese of Merseburg was established but dissolved in 981. In 1004 it was reestablished by King Heinrich II (Henry II).
Castle courtyard with entrance to Merseburg Cathedral