Imperial Cathedral Königslutter

 Lothar, born in 1075, came from the Saxon nobility. His homeland was the region between Braunschweig and Helmstedt. He is called "von Süpplingenburg" after his family's ancestral seat. His marriage to Richenza von Northeim brought him extensive property and sovereign rights. From 1106 Lothar was Duke of Saxony.
 
After the death of the last Salian emperor, Henry V, in 1125, a royal election was held in which Lothar was able to prevail against his competitors. The conflict that then broke out with the defeated Hohenstaufen Frederick II and his brother Conrad overshadowed almost the entire reign of Lothar. Conrad had himself elected anti-king and tried to gain a foothold in Italy. Lothar found support in the fight against his opponents from the Bavarian Duke Henry the Proud. He tied the Welf firmly to himself by giving him his only daughter Gertrud as his wife. He also gave his son-in-law the title of Duke of Saxony and consistently groomed him to be his successor. From the beginning, Lothar's goal was to establish a new dynasty - he envisioned a Saxon-Welf rule. Source:
 koenigslutter-kaiserdom.de/default.asp?LNG=DE&NAV=66

The Imperial Cathedral, dedicated to the apostles Peter and Paul, was founded in 1135 by Emperor Lothar III as a Benedictine abbey church and burial place for himself and his family. The Romanesque building was completed around 1170 under Henry the Lion after Lothar's death and the transfer of the empire to the Hohenstaufen dynasty. The church building is a cross-shaped pillar basilica, which was 75 m long and 18 m high, which was enormous for the time. The Imperial Cathedral was built at the highest point in the town. The cathedral is one of the most important Romanesque cultural monuments in Germany and was the first large vault north of the Harz Mountains. It was designed as a symbol of imperial dignity and is of equal importance to the Salian Imperial Cathedral in Speyer. The building shows the direct succession to northern Italian churches such as the cathedrals of Modena, Verona and Piacenza.
Source: Wikipedia

Recommendable. Great area with cafe