The former president, then a New York real estate developer, signed a copy of his book, “The America We Deserve,” to Giuliani, who was the Republican mayor of New York City at the time in January 2000.
“To Rudy ― the best mayor N.Y.C. has ever had! I promise never to run against you ― Donald,” the note reads.
The item was sold on RR Auction, an auction site specializing in historic artifacts, autographs and memorabilia, for $54,143 on Wednesday, according to the site.
RR Auction said the item had been certified, but did not specify whether it was sold by Giuliani or another party.
Sixteen years after the date on the note, Trump began his tenure in the White House, during which time Giuliani served as his personal attorney.
Giuliani is now under federal investigation and named in multiple lawsuits over work he did in that role, including a $1.3 billion lawsuit from Dominion Voting Systems seeking damages for lies spread by Trump and his allies about electoral fraud.
Under a mountain of legal fees, Giuliani is reportedly close to broke and receiving no help from Trump.
The first-edition copy of “The America We Deserve,” published in January 2000, is in “very fine condition,” according to the auction house.
“A remarkable New York City association, long pre-dating their controversial White House years,” the auction house’s description reads.