door bars. There is little record of door handle development between the Fall of Rome and about 1000 CE. The oldest European doors include the Bernward Doors and the Westminster Abbey door. The Bernward doors have large decorative ring-shaped handles of a type that became common on decorated doors from that period onwards. The Westminster Abbey door features a sliding bolt that can also function as a handle. From at least the Middle ages blacksmiths made drop latches which could be opened by a handle connected to the latch by a split pin passing through the door. Taking the form of a ring or strip, these handles could be elaborate and decorated but were universally made of metal. It can be speculated that since the task of making door hardware fell to the blacksmith, the use of turned or carved wooden knobs was not convenient. Wooden latches are also known from this period. A finger hole could be made that allowed the user to raise the latch from the other side of the door. The finger hole would double as a grip or handle. In another common design, transferred motion to open the latch was effected by a string passing through the door, which could be withdrawn from the inside to effectively lock the door to outsiders. In this case the door might also have a basic handle carved or turned from wood. From about mid-17th Century, drop handles were increasingly replaced by forged vertical handles formed as a bracket fixed to the door at the top and bottom of the bracket. Vertical handles with an incorporated latch mechanism, known as Suffolk latches were developed. By the mid-18th Century, forged vertical handles were being were being replaced by cast vertical handles, including the Norfolk latch. The early 17th Century also saw metalworking of a standard that allowed mortise locks and latches and compact rim locks and latches to be made for use in the most expensive buildings. These locks used a twisting motion to operate, accelerating development in decorative door knobs. The Industrial Revolution dramatically reduced the cost of lock and latch manufacture with lock designers including Barronin, Chubb and Bramah competing against each other around the end of the 18th century. From the 18th century, a wide variety of lever handles and knobs started to be produced, with designs determined by local aesthetic preference and technology. Knobs could be