Expression "you are ancient of days"

[Sara_h]

HI,
I would like to know what the expression 'you are ancient of days' means.
Just to add, I've come across it while reading one poem and since then I can't find the meaning, although I've looked it up in many dictionaries. So , the only hope is your advice or any suggestion.

[Mister Micawber]

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It is a stylized and euphuistic way of saying 'you are old'.
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_________________
Native English teacher at Mister Micawber's

[Sara_h]

Thank you a lot.