This appears to be a leather book cover used to protect a book. The binding cord (inside bottom of cover) was brought up and through the middle pages of the book to help hold it in place and keep the book from slipping down while being read. Cannot determine the age of this, but it is a beautiful piece - well used as seen from the wear - mostly likely a religious person due to the picture tooled on the cover.
Some hisotry: Up until the early 19C books were not bound. Publishers would sell the pages independently and the purchaser would have to pay for a binding (if not bound they would simply sit in a box and be read page by page). The bindings were usually undecorated and weak, so independent book/dust covers were used to protect the book as well as add a decorative flair. These were commonly made out of leather, vellum, linen, animal fur and other materials. Paper dust jackets were being made more commonly in the later 19C but they were so easily torn when a book was opened that they were discarded like wrapping paper at the book stores when the books were put on display to sell - and the actual book bindings were going from plain to decorative. After 1900, the economics of publishing caused book bindings to become more expensive to produce decoratively. In the early 1900's paper dust jackets were being produced cheaper by the publisher and were more elaborate than the books themselves. Thus, we have a twist here that the dust covers became more valuable than the book - example case being: "Dust jackets from the 1920s and later were often decorated in art deco styles which are highly prized by collectors. Some of them are worth far more than the books they cover. The most famous example is the jacket on the first edition of The Great Gatsby by F. Scott Fitzgerald, published in 1925. Without jacket, the book brings $1,000 or so. With the jacket it can bring $20,000 or $30,000 or more, depending on condition. One copy in a near mint jacket was listed for sale in 2009 for half a million dollars." So, once again independent leather book covers became popular to protect the dust covers. They are still used today.