Cathedrals of Mainz, Worms and Speyer
Mainz Cathedral was built by archbishop Willigis of Mainz, then regent of the empire, in the years after 975. Henry IV also contributed to the building after 1081. Mainz Cathedral was the coronation site for Philipp von Schwaben, Frederick II, and Henry Raspe. Also Henry II (in 1002), and Conrad II (in 1024) were crowned in the cathedral at Mainz, but both presumably in the preceding building, since the present cathedral was consecrated in 1038 after their coronations.
Other Imperial Cathedrals
Less well known is that the Salian built basilica in Königslutter, under the reign of Lothair III, also is traditionally called an Imperial Cathedral. The Cathedral in Bamberg, built under reign of Henry II, where the only canonized married couple has their grave, also has the same status. Aachen Cathedral and the Frankfurt Cathedral (Cathedral of Saint Bartholomew) in Frankfurt were also described as imperial cathedrals because they were the coronation cathedrals of emperors and kings.