Simple past tense and past participle of hearken.(verb)
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Use "hearkened" in a sentence
"I just heard a rumour Neil worked in animation bg painting years ago for disney; will have to ask Betty next time I see her; and I will mention that it was a treat to see his name hearkened to on a blog with such fine painting."
"I would not believe he had therein hearkened to my voice; I could not say that he had saved with his right hand and answered me (Ps. lx."
"Barry Sternlicht, on a Friday conference call hearkened back to near 20% returns on residential mortgages in 2009-three times the gains the managers had expected."