testify horror

Hello,
In "Melmoth The Wanderer" by Charles Robert Maturin there are these passages, I need help to understand "testify horror."

"it was agreed, in a chapter extraordinary, to surrender him to the power of the Inquisition. He testified great horror when this determination was made known to him" (He is the monk.)

"Why did you testify such horror at the funeral of Father Olavida?'—'Every one testified horror and grief at the death of that venerable ecclesiastic, who died in the odour of sanctity."

Thanks 👁 Smile :)

Testify - WordReference.com Dictionary of English
WordReference Random House Unabridged Dictionary of American English © 2021

1. to bear witness to; affirm as fact or truth; attest.
2. to give or afford evidence of in any manner.
3. Law to state or declare under oath or affirmation, usually in court.
4. to declare, profess, or acknowledge openly.

This is rather an old use of testify that is, currently, rare. It is rather dramatic (as suits the subject of the book) and is probably best understood as "speak about."