A Hebrew Bible more than 1,000 years old and described as “one of the most important and singular texts in human history” by Richard Austin, global head of books and manuscripts at Sotheby’s auction house, will be on exhibition tour in Israel and the U.S. before it will be auctioned by Sotheby’s in May.

The Hebrew Bible is the foundation of the three Abrahamic faiths: Judaism, Christianity and Islam. Scholars have long been aware of the codex named after renowned Judaica collector David Sassoon (1880-1942), but it has remained largely out of public view, Sotheby’s said. It is believed to be the first and most complete codex, or manuscript in book form, of the Hebrew Bible. It was written out by a single scribe on nearly 400 parchment sheets. In the centuries prior to its writing, Jews relied on oral tradition passed down through generations to understand and preserve the message of the Bible. Only portions of biblical texts in scroll form existed prior to the codex; these came to be known as the Dead Sea Scrolls.

After changing hands a few times, the Bible ended up in a synagogue in northeast Syria, which was destroyed in the 13th or 14th century. Then it disappeared for nearly 600 years. In 1929, it appeared for sale in Frankfurt, and was bought by Sassoon for 350 British pounds. The current owner purchased it in 1989. When auctioned, it is expected to be sold for an estimated $30 to $50 million.