Battle of Vlaardingen The Battle of Vlaardingen was fought on 29 July 1018 . The German emperor sent an army towards western Frisia to subdue the rebellious Count Dirk III . However , the imperial army was defeated by the Vlaardingers and fled in panic . Our knowledge of the battle is based on three chronicles , written shortly after the date : " De diversitate temporum " by the monk Alpertus of Metz , the " Chronicon " of Thietmar , bishop of Merseburg , and in the Cambrai Bishop ’ s " Chronicle " . Also , recent archaeological discoveries shed some light on Vlaardingen in the 11th century . Political background . In the early Middle Ages , Vlaardingen was part of the German Empire . The emperor at that time was Henry II . The north - western part of the empire , Lower Lotharingia , was ruled by Duke Godfrey of Verdun . Frisia , the most peripheral part of the duchy , fell under the office of Adalbold , bishop of Utrecht , and under Dirk III , to whom the coastal defence in the west had been delegated . Count Dirk had his power base in Vlaardingen , along the banks of the Merwede , where it merged with the Maas River . The causes . Emperor Henry II organised his expedition against the Frisians and their count for two reasons . Firstly , the emperor wanted to clear the trade route between the port of Tiel and England : Dirk III forced the sailors who passed by on the Merwede to pay a heavy tribute , and thus he endangered commerce and the tax incomes of the emperor . Secondly , the rebellious count had illegally occupied lands that were claimed by the bishop of Utrecht , and had even built a castle there . The bishoprics of Liege , Trier , and Cologne as well as several abbeys also had possessions in the region . The preparations for the expedition . At Easter 1018 , Emperor Henry II summoned a Reichstag in Nijmegen . He listened to the complaints of the merchants from Tiel and the Bishop Adelbold of Utrecht . Henry assigned Bishop Adelbold and Duke Godfrey to organise a punitive expedition against the rebellious Count Dirk . Within a few months , an army would be assembled in Tiel , the most important port in the Low Countries . The army would sail west , along the rivers Waal and Merwede , to Dirk ’ s stronghold in Vlaardingen . Three more bishops would supply troops : Balderic II of Liege , Gerhard of Cambrai and the Archbishop Heribert of Cologne . Bishop Balderic participated personally in the trip to Vlaardingen . Shortly beforehand , he had a new crypt constructed under the Basilica of Our Lady in Maastricht , which had collapsed on the day of his departure . This turned out to be a bad omen , because on the way downriver with the imperial fleet from Tiel to Vlaardingen the bishop fell ill . At Heerewaarden he left his ship and died on the very day of the battle . The size of the armies . The numbers of soldiers mentioned in the chronicles are questionable . According to Thietmar , more than three imperial legions were killed , which implies that Henry II ’ s army may have counted between 3000 and 20 , 000 warriors ( depending on the definition of a legion ) . The Cambrai Chronicle states that in Vlaardingen " a thousand have put even twice ten thousand to flight " , so the emperor would had sent 20 , 000 troops . However , this is only a literary quotation from the Bible ( Deuteronomy 32 : 30 ) which cannot be considered a realistic indication for the actual numbers on the battlefield . Verbruggen suggests that around the year 1100 , armies usually comprised a few hundred warriors . Possibly Dirk III could have had a few hundred men at his disposal . It seems overdone for the emperor to send thousands of professional soldiers against them . A number of about 1000 imperial warriors seems more likely . The course of the battle . The fleet with the imperial army drifted down the river and moored at Vlaardingen . After disembarkation the army marched towards Count Dirk ’ s castle . The locals , who had seen the fleet approaching , had withdrawn within the castle and " on higher grounds " . Initially , Godfrey lined his men up around the castle , but then he ordered them to march towards a flat field , because it would be difficult to cross the ditches that were dug all over the place . During this manoeuvre , the Frisians unexpectedly appeared from an ambush and attacked . Someone cried out that the duke had been killed , upon which panic broke out . The imperial warriors hurried back to their ships , which had been moved to the middle of the stream by now , because of the lowered tide . They sank away in the soggy river bank or they drowned . Meanwhile , the Frisians in the castle gestured and shouted to their countrymen on the higher areas to attack the survivors from the rear . The fleeing soldiers were finished off with javelins . Only towards the end did Dirk III appear : he rode out of the castle , with a few retainers . They hurried towards Duke Godfrey , who was still alive and fighting , but had been cornered by the Frisians . Thanks to Dirk ’ s intervention the duke was not killed . Dirk captured Godfrey , and took him to his castle . This ended the battle . The number of casualties suffered by the imperial army was enormous , while the losses on Dirk ' s side were minimal . The aftermath . After the battle , the opponents hurried to make peace again . Duke Godfrey was released promptly , and he arranged a reconciliation between Bishop Adelbold and Count Dirk III . Both parties probably realised that the defence of the Frisian coast against possible Viking attacks was more important than the quarrels between themselves . Nothing is known about the arrangements that the opposing parties made . It is likely that Dirk III had to make some concessions in order to obtain reconciliation , but concessions too were made on their part by the bishop and the emperor . One of which being , perhaps , that a promise was given to leave the count alone . In any event , no more armed conflicts have been recorded along the banks of the Merwede for three decades after the Battle of Vlaardingen . The location . The early medieval chronicles do not make clear exactly where in Vlaardingen the events took place or which manoeuvres the forces made . There have been several theories about the location . According to the latest views , the movements of the troops , the actual battle , and the flight , all occurred in the present Vettenoordse polder : a limited area , measuring about 500 x 500 metres , west and south of the centre of Vlaardingen . Vlaardingen ’ s town archaeologist Tim de Ridder suggests the church hill in the centre of Vlaardingen as the most obvious place for Dirk III ’ s castle . From this spot one has a view over the Merwede , the port , the count ’ s farmstead and the surrounding area , making it a strategic position . Recently , ground radar and tracer investigations on the church hill revealed a circular shape , a few metres below the church floor , with a diameter of 27 metres . The material the ring was constructed with is unknown . Because of the location it is hard to carry out any further investigations : in the 12th century , the church has been built straight on this spot . The precise age of the ring is also unknown , but it must date from before the 12th century . It is tempting to regard this discovery as the remains of a ring castle , built around the year 1000 by Count Dirk III . Earlier studies located the battle a few kilometres away from the present town centre . Rotterdam ’ s city archaeologist Hoek placed the battle three kilometres to the west , around the present municipal boundary with Maassluis , while De Graaf placed it two kilometres to the east , in the Babberspolder . Both views are unlikely . In the 18th and 19th century , historians stubbornly maintained that Dordrecht , not Vlaardingen , must have been the scene of action . Dordrecht is also situated along the Merwede , 25 km upstream . The ' Battle of Dordrecht ' can be found among several historians from that era , and it is still suggested by the odd modern historian . This hypothesis is untenable , not only because the sources about the battle in 1018 mention only Vlaardingen and not Dordrecht , but also because Dordrecht in the early 11th century was merely the name of a small river . The name of the place first appeared halfway during the 11th century , and no military stronghold is mentioned anywhere . There is no archaeological evidence for an 11th - century settlement . Only after the floods of the mid - 12th century , which dramatically altered the flow of the rivers , would the town acquire some importance . After 1150 , Count Floris III established a toll in Dordrecht , and gradually it became the major town in the county of Holland . But that was long after 1018 . Modern historians relegate the stories about Dordrecht to the realm of fiction . Why has Dordrecht been considered the location of the Battle of Vlaardingen for so long ? The origin of this misconception lies in the " Rymchronyk " : a famous forgery , attributed to a Klaas Kolyn , a monk from Egmond Abbey who allegedly had put the history of Holland into verse in the 12th century . In reality , this Klaas Kolyn never existed and the verse chronicle was in fact written around the year 1700 . It says , among many other things , that Dirk III founded a fortification and a village along the Merwede , that he named the settlement ' Dordrecht ' , and that the famous battle in 1018 was fought on that location . The authoritative historian Jan Wagenaar believed this story , and invented the year 1015 for the founding of the town of Dordrecht . Wagenaar has been followed by many colleagues . Afterwards , he admitted that he had been fooled , and subsequently none has seriously believed the authenticity of Klaas Kolyn . Still , the idea that Dordrecht was founded in 1015 and that is was the scene of the battle of 1018 has persisted . The significance of the Battle of Vlaardingen . The Battle of Vlaardingen can be considered as the starting point for the independent county of Holland . In 1018 , in Vlaardingen , Dirk III demonstrated that he would not be told what to do by any overlords . Later in the 11th century , German kings and emperors , and the bishops of Utrecht , made further attempts to subdue the counts of West Frisia . They almost succeeded when Duke Godfrey ' the Hunchback ' and Bishop William drove the young Count Dirk V out of Frisia . However , Dirk regained his county , with the help of the Flemish Count Robert . In February 1076 they killed the duke and in June 1076 they defeated the bishop in the Battle of IJsselmonde .