Where does “non-the-les” come from?

non-the-les (Middle English) comes from Middle English no-the-les, from Old English nā þē lǣs.

Ancestry of “non-the-les”, step by step

Step	Language	Word	Meaning
1	Middle English	no-the-les	—
2	Old English	nā þē lǣs	—

non-the-les — Etymology, Origin & Word History | Etymology Explorer