* When was the essay "Nature" by Ralph Waldo Emerson written? This essay was published in 1836.
* When was the concept of "Nature" as a philosophical or literary theme established? This is a much broader question with roots in ancient philosophy and literature. The concept of nature as a source of inspiration, beauty, and moral guidance has been explored for centuries.
* When did the word "Nature" first appear in the English language? The word "nature" has been used in English for over a thousand years, with its roots in Latin.
Please clarify your question so I can give you a more precise answer!