19. The Hourglass
The hourglass became a widely used timekeeping device during the Middle Ages, valued for its simplicity and reliability. Sailors relied on hourglasses to mark passing hours at sea, while monks used them to regulate daily prayers and routines. Unlike other medieval timers, hourglasses were portable and unaffected by weather or darkness. This practical innovation helped bring greater accuracy and order to daily life, both on land and across treacherous oceans.
