Clement Clarke Moore of Chelsea was a professor of theology and Hebrew and a biblical scholar at the General Seminary located in the same neighborhood. All of his scholarly books remain in print but they did not bring him lasting fame except for a poem he wrote for his children that he shared with his friends and family. His poem, "A Visit From St. Nicholas," written in 1822 opens, "'Twas the Night Before Christmas." He described Santa's sleight being pulled by eight reindeer and gave them their names. Moore declared Santa arrived on Christmas Eve, December 24. It has been a classic since its first appearance in the Troy Sentinel in 1823. In 1837 Clement Clarke Moore, a biblical scholar in New York City, allowed his name to be attached as author and, in 1844, he included the piece in his own book, "Poems." Moore explained that he had written the poem on the Christmas eve of 1823.
http://www.iment.com/maida/familytree/henry/writinghenryjr.htm#poems makes the claim that Henry Livingston (1748-1828), a Poughkeepsie New York poet, wrote the poem. This Yale University graduate was minister of a Dutch Reformed Church in New York City before becoming president of a theological seminary in Canada. He published his poetry anonymously or under a pen name.
Livingston's descendants claimed they had a manuscript version of the poem that was destroyed in a fire. Anyone can put something in writing so that is no proof by itself. One must ask why Livingston kept quiet when this poem became popular. He died in 1828 five years after the poem was published. None of his descendants in public questioned Moore's claim while he was alive. To put this controversy to rest, we need a sophisticated computer analysis. Right now, I would go with Clement Clarke Moore as the author.
Who wrote the Bixby letter was a source of controversy settled by Michael Burlingham. This was a letter that Abraham Lincoln wrote to the widow Bixby on the supposed loss of her five sons in the war. John Hay, one of Lincoln personal secretaries, always said he wrote the letter and his boss signed it. Burlingham looked at a scrapbook that Hay kept in which he reiterated the claim. Then Burlingame did a search of a usual word "beguiled" which Lincoln never used in his writing but that Hay did. He also compared their styles and found that the letter more in style of Hay than Lincoln. Lincoln's writers have been put into a computer data base while Bulringham had to read every thing that Hay had written. It also turned that ate widow Bixby had lost two sons, not five, and she was Confederate sympathizer who destroyed the letter that Lincoln sent her. We have the letter because the adjutant general of Massachusetts who received the original to forward to her sent a copy to the newspapers. She also ran a whorehouse in Boston. So much for romance! So mcuh of history!
Ultimately, courts of law have ruled on the issue of who is the rightful author, inventor or creator. For example, Famousplagiarists.com recounted on May 10, 2000: "When the 9th Circuit Court upheld the original $5.4 million judgment against Michael Bolton for his copyright infringement of the Isley Brothers' "Love is a Wonderful Thing", the 3-0 decision sent a clear message that derivation--even subconscious derivation--can end up costing a musical plagiarist quite a hefty sum of money."
On the other hand, BBC News reported on 19 September 2002: "Pennsylvania-based writer Nancy Stouffer claimed Rowling had lifted ideas from her own book The Legend of Rah and the Muggles and wanted to be recognized as Harry Potter's creator. But a court in New York threw out the claim for plagiarism against Rowling, US publisher Scholastic and film producers Warner Bros, ruling Ms Stouffer had lied and altered documents to support her case."
One thing to be sure, when there is money or fame to be had; there are people ready to rush forward to claim they were the true authors. Supporters of Gustave Whitehead claimed that he had the first successful powered flight as early as 1898 but other than a sketch no other evidence survives to back this claim. Lyman Gilmore also made a similar claim but alas just like the Livingston family his alleged proof also burned up. The Smithsonian championed its Secretary Stanley Langley for two score years even though his planes crashed until it agreed in writing to state the Wright Brothers were the first to fly to get their flyer for permanent display. The Wright Brothers carefully documented their claim through photographs and eye-witnesses.
In "The Telephone Gambit: Chasing Alexander Graham Bell's Secret," journalist Seth Shulman argues that Bell aided by aggressive lawyers and a corrupt patent examiner” got an improper peek at patent documents Elisha Gray had filed, and that Bell was erroneously credited with filing first. The only problem is that for next twenty-five years, this became the most litigated patent in American history as Bell fought off over twenty legal challenges such as Western Union. My belief is if there was a smoking gun to be found, it would have been found because big bucks were at stake. Also, looking at Bell's character of a lifetime, I don't think he would be capable of engaging in such unethical behavior.