It seems unlikely he is actually the richest. Historically many individuals have amassed pretty fabulous amounts of wealth. From some of the history I have read, Marcus Licinius Crassus or Lorenzo de' Medici seem to have had substantially more purchasing power, at least relative to the times they lived in.
For example, I do not see Bezos building anything I would compare to cathedrals.
For example, I do not see Bezos building anything I would compare to cathedrals.