The Nuremberg Mahzor has travelled 679 years and crossed hundreds of hands on its long journey to the Israel Museum's conservation department. Going on display this week for the first time since its restoration, the leather-bound, illuminated Hebrew manuscript is the most complete existing Ashkenazi prayer book and boasts the largest collection of commentaries and liturgical poems (piyyutim). At 50 cm. long, 37 cm. wide and weighing 26 kilos, it is among the largest medieval illuminated manuscripts. In its 1,042 pages, the tome guards the mysteries of the wealthy 14th-century Jewish-German family who commissioned it, the anonymous scribes and artisans who penned and decorated it, and the thieves who removed and sold 11 of its pages. Some small facts are known: An inscription shows that a man named Joshua, son of Isaac, commissioned the collection. "We assume that he was a learned man who studied liturgy and its meaning, as the hundreds of commentaries indicate," says Anna Nizza, the exhibit's curator. "Seemingly, he was also wealthy enough to afford a huge amount of parchment, professional scribes, a designer, colorists, a binder and an editor who decided the context and what to emphasize." Parchment was prohibitively expensive because it was made of animal skins. It may have taken 250 animals to make enough parchment for 1,000-plus pages, says Michael Maggen, head of the museum's paper conservation laboratory. Maggen and Nizza have pored over the manuscript for the last two years, looking for clues and preparing for its first public display in a museum. The pigments in the 22 illustrations were the easiest to identify, all typical of 14th-century illustrated manuscripts: black from carbon; green from malachite; imperial blue of lapis lazuli and azurite; pure 24-karat gold leaf; and red vermilion cinnabar of mercury sulfite. Arsenic, which may have comprised the yellow, was also a typical colorant. The humanized animal forms and other design motifs were typical of the Rhine Valley and southern Germany at the time. Damaged pages were found to have been repaired with parchment from discarded Esther scrolls. Clues were also hidden in the ornamentation repeatedly emphasizing certain words, suggesting that the main scribe's name was Matan or Matanya, and that the scribe of the commentaries was named Ya'acov. "It's like a Harry Potter film," says Maggen. "You learn from the details that combined form small clues." THE BIGGEST mystery appears to remain the fate of the manuscript: How did it end up in the Nuremberg Municipal Library, where it was stamped and numbered, after it was commissioned for family use "through the generations"? Why were 11 pages stolen, only some of them illustrated? How did some of the missing pages end up in Frankfurt and where are the rest? Researchers are convinced that the manuscript was transferred to the library in 1499 when Nuremberg and other nearby areas in Germany expelled their Jewish communities. In the second half of the 17th century, non-Jewish scholars published general commentary about the Nuremberg Mahzor, marking the first time mention of the book was found in a public library. In the 1880s, German rabbi Bernhard Ziemlich discovered that 11 pages were missing and theorized that soldiers from Napoleon's army had been the thieves. In the early 20th century, five of the stolen pages turned up in the collection of the Goldschmidt family of Frankfurt. In 1937, a son-in-law who inherited the pages gifted one to Salman Schocken, the German-Jewish publisher and book collector. Schocken later bought another three from him. Post-World War II, Schocken petitioned the Nuremberg Library to acquire the mahzor in its entirety. In 1951, German authorities agreed to sell it to the library at the Schocken Institute for Jewish Research in Jerusalem as part of Schocken's restitution. It was in the Jerusalem library for 50-plus years until Dr. David and Jemima Jeselsohn of Zurich purchased the manuscript and the four missing pages and gave them on long-term loan to the Israel Museum to be restored, conserved and put on display. After eight months, Maggen finished restoring the binding elements, cover, clasp and damaged pages, reintroduced the lost pages and reorganized several pages bound in incorrect order in the 18th century by the Nuremberg Library staff. Maggen still hopes to be in contact with other researchers for further possible investigations. James Snyder, director of the Israel Museum, called the Nuremberg Mahzor an important loan to the museum's collections of Hebrew manuscripts. "It offers unique insights into Jewish life during a very long, important and rich period of European Jewish history," he says.