In the mid–19th century, interest in Roman Catholic circles in scholastic methodology and thought began once again to flourish, in large part in reaction against the "Modernism" inspired by thinkers such as Descartes, Kant, and Hegel, the use of which was perceived as inimical to Christian doctrine. The meaning and core beliefs of theological Modernism were never tightly defined; in large part, Modernism simply represented that which was attacked by Rome in 1907 as ‘the sum of all heresies’. Moreover, given that Modernism remained the perceived enemy of neo-Scholasticism throughout the late 19th and early 20th centuries, there were certainly changes over the decades in what was attacked. Certainly, however, common threads of thought can be detected. These include (1) the belief that revelation continued up to and including the present day and, therefore, did not stop with the death of the last apostle; (2) the belief that dogmas were not immutable and that ecclesial dogmatic formulas could change both in interpretation and in content; (3) the use of the historical-critical method in biblical exegesis.