Beep, beep! Ring! Riiinnggg! Your alarm clock is telling you to wake up. It may require you to push the snooze button—or if you’re really into high-tech, it may be inviting you to a friendly morning game of tag. But how did people wake up before alarm clocks were invented?

Some people hired others to wake them up. In the 1400s, town criers of the port of Sandwich, England, woke sailors with a weather report (a loud one!). Much later, some professional “knocker-uppers” used a pea shooter or stick to tap on windows. That roused customers.

Having humans stir you to rise in the morning would usually mean someone else has to stay up all night. But how would that person know when to sound the alarm? Sundials were some of the earliest time-keeping devices. They tracked the position of the Sun to tell time. But they were useless at night. Instead, ancient and medieval water clocks used water flow to show time passing. Water dripped out of or into bowls. Later, people also used sand hourglasses.

Greek philosopher Plato probably invented the first alarm clock. He added a tube to his water clock. It whistled to awaken sleepers.

Mechanical clocks were invented in the Middle Ages. Gravity pulled weights down to run a clock. The weights had to be wound back up for every cycle. These clocks caught on in churches and town belfries. A whole village could hear the bells strike the hours.

Over time, individuals owning clocks became more common. By the mid to late 1400s, some houses had their own heavy iron wall clocks. Many could be set to ring a bell at a certain time.

Some crazy alarm clocks have been created over the years too. Around 1837, French performer Jean-Eugène Robert-Houdin invented a clock that lit a candle after the alarm sounded. Modern-day alarm Clocky has wheels. It will run away, forcing sleepers to get out of bed to turn it off.

One is calling to me from Seir, “Watchman, what time of the night? Watchman, what time of the night?”— Isaiah 21:11