since the person being quoted has been dead for centuries, and not merely the 70 years required to shift something into the public domain, it's surely not 'plagiarism'! ;-)

besides which, it may not even be from a piece of writing... and even if it was, it couldn't have been copyrighted way back in the 6th century, as there was no such thing then...

plagiarism is the unauthorized use of copyrighted work... in the us, a copyright now lasts the lifetime of the originator plus 70 years... in most cases... it's a similar situation in the uk, though there are some exceptions, one of the most notable being jm barrie's 'peter pan'... and, in the us, the Sonny Bono Copyright Term Extension ...

hope this lays your fears to rest...

love and hugs, maia

Exactly. If they've been dead for a number of years, you're fine. If they're alive or recently deceased, you might still be okay, but it's more of a cause to worry.

not really, andreya... not in a novel, in any case... and that's what this poster is asking about... anyway, why should a novelist want to tout someone else's book?

the only reference to the source should be within the text itself, such as referring to who originally said it... such as:

The monk replied, "For me, as St. Columcille said, 'Christ is my druid now.' "