The artifact is an example of a motu proprio, (a Latin term, meaning, “on his own impulse”), a document issued by the Pope, or by a monarch on his own initiative and personally signed by him.
When issued by the Pope a motu proprio may be addressed to the whole Church, to part of it, or to some individuals. This particular letter is know as a fiat motu proprio. This designation is clearly visible in the upper portion of the letter.
A papal fiat designates a written document granting permission to a diocese or a religious order or an individual for whatever is being requested. The Holy Father writes in his own hand, Fiat et Petut, meaning “Let it be done according to Peter.” The first initial of the pope is the most common form of signature on a papal fiat.
What contributes to the rarity of the artifact is the short duration of his pontificate, which lasted less than two years.
Pope Alexander VIII was elected October 8, 1689, and this papal fiat was written just a month later.