Over the course of the early modern period, the classificatory concept of the three kingdoms of nature became an important heuristic principle in the descriptive and organizational systems of natural science. The Latin term regnum (“kingdom”; French règne, German Reich) became popular in the late 17th century through the encyclopedic work of the Swiss physician and natural historian Emanuel König [4], and it became exceedingly important as a concept particularly in the heyday of classical natural history, from the mid-18th century to the mid-19th. The kingdoms of nature - the an…