Battle of Kokenhausen The Battle of Kokenhausen ( Kokenhuza , ) was a major battle opening the Polish – Swedish War ( 1600 – 1611 ) . It took place on the 23 June 1601 near Koknese in Livonia ( now in Latvia ) . In the battle , Polish forces defeated the Swedish relief force and captured the besieging force , relieving the Polish garrison . The battle is notable as one of the greatest victories of the Polish hussar s , who defeated their numerically superior Swedish adversaries . Prelude . Kokenhausen was one of three major forts blocking the Swedish progress on the line of the Daugava River river . Swedish forces of about 2 , 000 under Carl Carlsson Gyllenhielm had been blockading the fortified town of Kokenhausen , located on Daugava River , between Riga and Daugavpils - since 10 March - after the arrival of Duke Charles with heavy artillery - laying a siege to it since 28 March . On 1 April the Swedes had taken the town but not the inner castle , which was still defended by a Polish garrison . Charles left about 2 , 600 strong besieging force , and moved north to Erlaa . The Polish relief army of 800 men under Krzysztof Mikołaj " the Thunderbolt " Radziwiłł arrived around 11 May and in turn started to besiege the Swedes ; it grew to over 4 , 000 with 16 cannons by mid - June . The Swedes decided to prioritize the relief of the Kokenhausen siege force . They have been reinforcing it with supplies through the river , but many of them have been captured by Poles on May 29 . A major Swedish relief force of about 2 , 000 under Carl Gyllenhielm has been defeated at Erlaa by 1 , 000 Poles under Jan Siciński in early June . Emboldened by the victory , other Polish detachments captured some nearby strongholds and harassed the Swedish units . The Poles did not assault Kokenhausen , however , as they were waiting for more artillery , and were content to starve the Swedes out . The Swedes did not give up on securing the site , however , and reinforced to 5 , 000 the Swedes under Gyllenhielm arrived on the morning of 23 June at Kokenhausen and attempted to break the Polish encirclement . Battle . The field of battle was raised along its edge with the Daugava for some one and a half kilometers to a width of about half a kilometer with the side nearest the river being steep and falling more gently towards the field . Gyllenhielm had about 900 infantry , 4000 cavalry and 17 cannons . Radziwiłł left about 500 infantry under Otto Denhoff with orders to maintain the siege , and took the field with the rest ( around 3 , 000 men , of which some 400 were infantry , 1000 Polish hussars , and 9 cannons ) . In addition to Grand Lithuanian Hetman Radziwiłł , the Polish forces also included the Field Lithuanian Hetman , Jan Karol Chodkiewicz . Polish cavalry first broke the Swedish left flank . The Swedish counterattack on the right flank , which while initially successful , was in turn broken by the Polish hussar counterattack . The Swedish infantry still held against the Polish cavalry , until being broken by the artillery fire . Gyllenhielm gathered some 2 , 000 cavalry but his troops refused to return to aid the infantry , and he was forced to retreat . Aftermath . The Poles lost about 200 men , the Swedes - 2 , 000 ( including almost all of their infantry ) . After the battle , the Swedish force besieging the Kokenhausen castle , which took no part in the battle , surrendered to the Poles . Swedish siege artillery was also captured . Both the hussar charges and artillery fire proved decisive in this engagement . The battle is notable as one of the greatest victories of the Polish hussar s , who defeated their numerically superior Swedish adversaries .