It is true that Leiden is an old city; its connection with Roman Lugdunum Batavorum is true though it is actually near the close-by town of Katwijk, whereas the Roman settlement near modern Leiden was called Matilo. However, there was a Roman fortress in Leiden in the 4th century. Leiden formed on an artificial hill (today called the Burcht van Leiden) at the confluence of the rivers Oude and Nieuwe Rijn (Old and New Rhine). In the oldest reference to this, from circa 860, the settlement was called Leithon. The landlord of Leiden, situated in a stronghold on the hill, was initially subject to the Bishop of Utrecht but around 1100 theburgraves became subject to the county of Holland. This county got its name in 1101 from a domain near the stronghold: Holtland or Holland.
Leiden was sacked in 1047 by Emperor Henry III. Early 13th century, Ada, Countess of Holland took refuge here when she was fighting in a civil war against her uncle, William I, Count of Holland. He besieged the stronghold and captured Ada.
Leiden received city rights in 1266. In 1389, its population had grown to about 4000 persons.
Siege of 1420
In 1420, during the Hook and Cod wars, Duke John of Bavaria along with his army marched from Gouda in the direction of Leiden in order to conquer the city since Leiden did not pay the new Count of Holland Jacqueline, Countess of Hainaut, his niece and only daughter ofCount William VI of Holland. The army was well equipped and had some guns.
Burgrave Filips of Wassenaar and the other local Hoekse noblemen assumed that the duke would besiege Leiden first and send small units out to conquer the surrounding citadels. But John of Bavaria chose to attack the citadels first.
He rolled the cannons with his army but one too heavy went per ship. By firing at the walls and gates with iron balls the citadels fell one by one. Within a week John of Bavaria conquered the castles of Poelgeest,
