Periodical processes with duration of cycles about 50 years (MMP-waves), observed in artistic style, were deduced earlier. As well analogous waves take place in the intensity of artistic life, artistic creativity, and related spheres. On the basis of the data on 5982 composers, 867 painters, 2741 persons of theatre, and 992 playwrights of the 12th – 20th centuries (relating to 40 European countries), evolutionary curves were built for the ‘intensity of artistic creativity’ in each kind of art. Most curves reveal hill-like long-term trend; against the background of this trend periodical oscillations were observed, some of them being synchronous both for different kinds of art and different cultural regions. The same level of the intensity would be obtained if the value of external forces is rather high and the value of internal forces is low, or vice versa. Dealing with MMP-waves we can see 50-year cycles. Studying Intensity waves we observe cycles with various periods (about 40-50 years). Such difference is likely to be connected with influence of external and internal forces.