not the completely proper word. A leitha (later "lede") was a human-modified natural river, partly natural, partly artificial. Leiden has in the past erroneously been associated with the Roman outpost Lugdunum Batavorum. This particular castellum was thought to be located at the Burcht of Leiden, and the city's name was thought to be derived from the Latin name Lugdunum. However the castellum was in fact closer to the town of Katwijk, whereas the Roman settlement near modern-day Leiden was called Matilo. The landlord of Leiden, situated in a stronghold on the hill (motte), was initially subject to the Bishop of Utrecht but around 1100 the burgraves 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 4,000 persons. Siege of 1420 In 1420, during the Hook and Cod wars, Duke John III 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 of Count William VI of Holland. Burgrave Filips of Wassenaar and the other local noblemen of the Hook faction 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 along with his army but one which was too heavy went by 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, Ter Does, Hoichmade, de Zijl, ter Waerd, Warmond and de Paddenpoel. On 24 June the army appeared before the walls of Leiden. On 17 August 1420, after a two-month siege, the city surrendered to John of Bavaria. The burgrave Filips of Wassenaar was stripped of his offices and rights and lived out his last years in captivity. 16th to 18th centuries Leiden flourished in the 16th and 17th century.