Keys and Leiden by tompt
Everywhere in the city you will encounter keys. A nickname for Leiden is Sleutelstad (keycity).Since 1293 the cityseal had St Peter on it. St Peter often has a key in his hand. This comes from the biblical text (Matthew 16: 19) in which Jesus gives Peter the keys to the heavens.
St Peter was patron saint of the city. And the main church was dedicated to him.
The official seal of Leiden now bears two keys.