Symbol of death, time
The hourglass was invented in Europe during the Early Middle Ages. It was created to aid in the telling of time. An hour had passed when the sand spilled out of one end. After that, the hourglass could be switched over to count another hour. Until the mechanical clock was invented, time was measured with hourglasses. Two triangles, one upside down on top of the other, make up the hourglass sign. Nature is represented by these triangles. The Earth is shown on the lower level, while the sky is represented on the upper level. The hourglass is a symbol of death since it estimates how much time a person has left. To depict the passing of time, some hourglasses include wings. On tombstones and in coffins, hourglasses have been carved. Gravestones have also been adorned with hourglasses. A flag with an hourglass insignia would be flown on pirate ships, indicating the amount of time their captives had left to live.