precedented

c. 1650 precedent +‎ -ed, possibly a back-formation from unprecedented.

precedented (comparative more precedented, superlative most precedented)

1. (rare, chiefly law) Having a precedent; not novel
   • 1905, George Pierce Baker & Henry Barrett Huntington, The Principles of Argumentation‎, page 660:

     We have a right to take any method that is legal and is precedented.

precedented

1. (rare) simple past tense and past participle of precedent
   • 2005, America The Book, “So You Want To Be A Precedent”, in (Please provide the book title or journal name)‎, page 92:

     "Is 'precedented' even a word?" you may ask. Well, it is now, Noah-fucking-Webster. I just precedented it.

• unprecedented