BOSTON, MASS.- Featuring nearly 1,100 lots, RR Auction's April Fine Autographs and Artifacts sale boasts a wealth of important historical material.

Highlights include a four-page handwritten letter by Ludwig van Beethoven about a proposed composition. The handwritten letter by Beethoven to his librettist, the court poet Friedrich Treitschke, asking him to help secure two hundred gold ducats payment for their planned opera 'Romulus und Remus.' The rare four-page letter emphasizes the "many sacrifices I have willingly made and am making for my art.” (Estimate: $300,000+)

"It's a rare and important handwritten letter by the musical genius, discussing both his financial difficulties and a long-contemplated but never completed work," said Bobby Livingston, Executive VP at RR Auction.

Also up is a significant pair of letters by the Wright Brothers about patents and contracts. The immensely desirable 1908 handwritten letters from the Wright Brothers, dating to their important demonstration flights in Europe and the States. The hugely desirable pairing of letters from legendary aviation brothers Orville and Wilbur Wright, both one page, and addressed to engineer and businessman Hart O. Berg, a Flint and Company representative contracted to help manage the Wright Brothers' business in Europe. Berg's wife, Edith, became the first American woman to fly as a passenger in an airplane when she joined Wilbur for a two-minute and seven-second flight at Camp d'Auvours in Le Mans, France, on October 7, 1908. (Estimate: $25,000+)

In addition to a super rare book autographed by Stephen Hawking, as an Institute of Astronomy researcher—one of the rarest autographs in science! The signed book: The Archaeology of the Industrial Revolution. First edition, first printing. London: Heinemann Educational Publishers, 1973. In 1968, Hawking joined the staff of the Institute of Astronomy in Cambridge, where he remained until 1973. This became the site of some of his most important early scientific breakthroughs in the study of singularities and black holes. At the end of his tenure at the Institute of Astronomy, Hawking published his first book, The Large Scale Structure of Space-Time, a highly technical work exploring the foundation of space itself and its nature of infinite expansion. This period also marked Hawking's physical deterioration from ALS, and he would soon lose his ability to walk and write; by 1975, he was confined to a wheelchair. Hawking autographs are of the utmost rarity, with this rare example exhibiting ironclad provenance. (Estimate: $25,000+)

Among Modern Music is a pristine Abbey Road Studios promo card signed by the Beatles in 1963. Desirable early Parlophone Records promo card of the Beatles during a recording session in the Abbey Road. Parlophone Records produced a small quantity of promotional photo cards in two formats—a horizontal version and a vertical one, both with pictures being shot by famed Beatles photographer Dezo Hoffmann while the Beatles were in the studio recording their first single, 'Love Me Do.' Almost all of these cards were signed on the reverse, because there was very little light area on the front of the cards for their signatures. Taken on September 4, 1962, the image shows the group in their final incarnation at the beginning of their storied career and the first promo card with new drummer Ringo. An ideal uninscribed example boasting a full set of crisp vintage signatures. (Estimate: $20,000+)

And from the Classic Entertainment category is a great signed photo of Bruce Lee as Kato. The vintage glossy photo from The Green Hornet television series. The recipient of the photo, Roger Kay, became Bruce Lee's first child student at his Seattle-based martial arts school, the Lee Jun Fan Gung Fu Institute, in 1960. Enhanced by its remarkable provenance, this boldly signed photo of Lee as the heroic Kato is an absolute treasure for enthusiasts of both vintage television and the Little Dragon. (Estimate: $20,000+)

The Fine Autographs and Artifacts auction from RR Auction began on March 10 and will conclude on April 13.