Mainz Cathedral or St. Martin's Cathedral (German: Mainzer Dom, Martinsdom or, officially, Der Hohe Dom zu Mainz) is located near the historical center and pedestrianized market square of the city of Mainz, Germany. This 1000-year-old Roman Catholic cathedral is the site of the episcopal see of the Bishop of Mainz.
Mainz Cathedral is predominantly Romanesque in style, but later exterior additions over many centuries have resulted in the appearance of various architectural influences seen today. It comprises three naves and stands under the patronage of Saint Martin of Tours. The eastern quire is dedicated to Saint Stephen.
The interior of the cathedral houses tombs and funerary monuments of former powerful Electoral-prince-archbishops, or Kurfürst-Erzbischöfe, of the diocese and contains religious works of art spanning a millennium. The cathedral also has a central courtyard and statues of Saint Boniface and The Madonna on its grounds.