At the end of the 10th century, Romainmôtier passed into the hands of Cluny Abbey in France. The abbots set about transforming the site into a monastic complex. Work continued for more than a century.
At the start of the 11th century, Abbot Odilo had a new church built. This was modelled on Cluny II, the second church constructed at the mother abbey in France. It bore all the hallmarks of Romanesque art, such as a barrel-vaulted nave, windows that allowed rays of light to penetrate deep into the interior and particularly thick walls that were able to support the vaults. A narthex would be added later.
Even today, the church at Romainmôtier remains one of the finest examples of Cluniac Romanesque art in Switzerland and Europe.