An interesting issue in the domain of history of science and ideas is the concept of similarity of historical personalities. Similar objects of research of philosophers and scientists indicate prospective influences, caused either from one another's reading or meetings, communication or even cooperation. Key methodological role in the surfacing of the sought similarities play the keywords extracted from their works as well as their placement in a philosophical and scientific term taxonomy. The case study examined in the framework of this paper concerns scientists and philosophers, who lived in ancient Greece or Renaissance periods and dealt, in at least one work, with the subject God. All the available data (scientists, studies, recorded relations between scientists, keywords, and thematic hierarchy) have been organized in an RDBMS environment, aiming at the emergence of similarities and influences between scientists through properly created SQL queries based on date and thematic hierarchy criteria.