pseudonymity

[sood-n-im-i-tee]

noun

Origin of pseudonymity

First recorded in 1875–80; pseudonym + -ity

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Indeed, that is an argument in favour of the pseudonymity of the Book.
The Expositor's Bible: The Book of Daniel
F. W. Farrar
The question of the pseudonymity of the book is still an open one.
Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2
Various
All hypotheses as to their pseudonymity or composition by different hands may be dismissed.
Encyclopaedia Britannica, 11th Edition, Volume 15, Slice 4
Various
Associated words: pseudonymous, pseudonymity, pseudepigraphous pseudepigraphy.
Putnam's Word Book
Louis A. Flemming
Mrime's pseudonymity was of short duration, but whilst it lasted it was impenetrable.
Main Currents in Nineteenth Century Literature - 5. The Romantic School in France
Georg Brandes