A mortise lock (also spelled mortice lock in British English) is a lock that requires a pocket—the mortise—to be cut into the edge of the door or piece of furniture into which the lock is to be fitted. In most parts of the world, mortise locks are found on older buildings constructed before the advent of bored cylindrical locks, but they have recently become more common in commercial and upmarket residential construction in the United States. The design is widely used in domestic properties of all vintages in Europe. History Mortise locks have been used as part of door hardware systems in the US since the second quarter of the eighteenth century. In these early forms, the mortise lock mechanism was combined with a pull to open the unlocked door. Eventually, pulls were replaced by knobs. Until the mid-nineteenth century, mortise locks were only used in the most formal rooms in the most expensive houses. Other rooms used box locks or rim locks; in contrast with embedded mortise locks, the latch itself is in a self-contained unit that is attached to the surface of the door. Rim locks have been used in the United States since the early eighteenth century. An early example of the use of mortise locks in conjunction with rim locks within one house exists at Thomas Jefferson's Monticello. In 1805, Jefferson wrote to his joiner listing the locks he required for his home. While closets received rim locks, Jefferson ordered 26 mortise locks for use in the principal rooms. Depictions of available mortise lock hardware, including not only lock mechanisms themselves but also escutcheon plates and door pulls, were widely available in the early nineteenth century in trade catalogues. However, the locks were still expensive and difficult to obtain at this time. Jefferson ordered his locks from Paris. Similarly, mortise locks were used in primary rooms in 1819 at Decatur House in Washington, DC while rim locks were used in closets and other secondary spaces. The mortise locks used at Monticello were warded locks. The term "warded lock" refers to the lock mechanism, while the term "mortise lock" refers to the bolt location. Warded locks contain a series of static obstructions, or wards, within the lock box; only a key with cutouts to match the obstructions will be able to turn freely in the lock and open the latch. Warded locks were used in Europe throughout