In 1866 , a coup d' Ã tat resulted in Cuza being exile ; he was not allowed into that part of the country . Prince Karl of Hohenzollern-Sigmaringen became the new leader , and was later called Prince Carol I of Romania . In a 1866 coup d' Ã tat , Cuza was exiled and replaced by Prince Karl of Hohenzollern-Sigmaringen , who became known as Prince Carol of Romania .