The history of the study of the population of Azerbaijan, except for its individual fragments, has not yet been studied. Therefore, in the study and development of the demographic knowledge of Azerbaijan, the ancient demographic views of Azerbaijani people are of great importance. From the very first steps of the scientific study of demographic knowledge, one of the main issues was the problem of sources. Actually, it spontaneously arose at the end of the primitive society in the form of cave paintings and customs. These customs gave rise to an increase in population. The people of Azerbaijan are one of the most ancient peoples of the world. In Azerbaijan, even in antiquity, there was a great tendency to have many children. To protect ourselves and all our loved ones from all sorts of troubles, evil spirits and misfortunes, our ancestors asked for help from natural phenomena. According to the beliefs of our ancestors, the Sun and fire, water and stone are the main sources of heat, light and fertility. All these issues of historical demography are also highlighted in the writings of some Azerbaijani historians, archaeologists and ethnographers.