A Calendar Clock is a clock that incorporates a mechanism displaying the date in addition to the time. More sophisticated examples may also indicate the day of the week, month, phases of the moon or even leap years. Popular during the nineteenth century, calendar clocks were produced as mantel clocks, longcase clocks and wall clocks, demonstrating the increasing complexity of Victorian clockmaking. Antique calendar clocks are admired for both their technical ingenuity and decorative appeal.