The remarkable find, made during the valuation of a house contents in Manchester, is expected to bring more than £100,000 when it is offered for sale in Macclesfield in November.
Valuer Bill Forrest was first shown a box of Jewish prayer books when preparing the estate of a Rothschild family member for sale earlier this year.
The 20-leaf manuscript, punctuated by numerous coloured vignettes that set forth the order of the Passover Seder, was found buried towards the bottom but apparently no worse for its recent neglect. It retained its original Viennese binding and was in fresh condition, save the minor staining on folios whose text relates to the ritual consumption of food.
Research subsequently found that the scribe and artist was Aaron Wolff Herlingen of Gewitsch, Moravia, also known as Aaron Schreiber and a key figure in the renaissance of Hebrew manuscript art that began in Vienna in the early 18th century.
Schooled in the multiple languages of the Holy Roman Empire, in 1736 Herlingen was made scribe of the Imperial Library in Vienna and is known to have completed around 40-50 Haggadot in his career.
Mr Forrest is currently piecing together the history of the new discovery, which is already making waves in the Judaica collecting world.
Herlingen's signature appears on the title page alongside the date 1726 and the name Mendel Oppenheimer. It seems possible the manuscript was commissioned to mark the birth of Emanuel Mendel Oppenheimer (1726-80), the first child of Samuel Emanuel Oppenheimer of Vienna and a close descendant of the great banker and imperial court diplomat Samuel Oppenheimer (1630-1703).
A later pencil inscription reads: No.47 Exposition du Albert Hall, an indication that the Haggadah had been an exhibit at the Anglo-Jewish Historical Exhibition held at the Kensington landmark in 1887. At the time, the vendor's family lived in Belgium but moved to London shortly after the Nazi invasion.
Raising the possibility that this is also an object of great value is the knowledge that another Herlingen Haggadah, apparently one of only a small handful of survivors now in private hands, was sold in New York last year. That larger version, numbering 33 leaves and including a map showing thetribulations of the Exodus, made an eye-watering $800,000 (or $962,500 including buyer's premium) as part of the Important Judaica sale at Sotheby's New York on December 2012.
Adam Partridge expect their manuscript to prove the highlight of their specialist sale of Judaica on November 22 when it carries an estimate of £100,000-150,000.
• By coincidence, Boston auctioneers Skinner will offer a Haggadah decorated en grisaille by Aaron Wolff Herlingen in their Judaica sale on October 3. Dated 1735, this unrecorded example was produced during the artist's stay in Pressburg (now Bratislava, Slovakia).
An old inscription reads: "This Haggadah belongs to the learned Itsik, son of Abraham Rofe of Lisa (Littau, Czech Litovel), who lives in the town of Hultschin." It carries an estimate of $200,000-300,000.