The Castle Steward for The Castle of Muskogee has just this semester asked about how a clock might be built for their new clock tower.  It has to be non-electric and should be as "period" as possible.  Their period is the reign of Henry VIII.  This is still about 20 years before the birth of Galileo and almost 100 years before Huygens first real pendulum clock.  About the only two kinds of clocks in Henry's day were clepsydra (water clocks) which went back to Greeks, Roman, and Egyptian roots and the verge and foliot mechanism (which may have derived from an alam mechanism that was used in some clepsydra).  About 1270AD some unknown person used it for time keeping puposes.  We may therefore be building some kind of Medieval clock for public display this semester.  If you're interested I have an operating LEGOs model of the verge and foliot mechanism for you to peruse as well as some preliminary designs and calculations.