Modernism refers to theological opinions expressed during the late 19th and early 20th centuries, but with influence reaching into the 21st century, which are characterized by a break with the past.
Catholic modernists form an amorphous group. The term "modernist" appears in
Pope Pius X's 1907
encyclical Pascendi dominici gregis. Modernists, and what are now termed "Neo-Modernists", generally do not openly use this label in describing themselves. Traditionalist Catholics, however, continue to use the term.