 The truce of Zborov did not last long , and in the spring of 1651 Khmelnytsky 's Cossacks begun advancing west again . On June 1 , 1651 Wiśniowiecki brought his private army to face the Cossacks in Sokal . He commanded the left wing of the Polish @-@ Lithuanian army in the victorious Battle of Berestechko on 28 – 30 June . The Polish @-@ Lithuanian army advanced after the retreating Cossacks , but on July 17 the King " left the whole army to Potocki ... and having given the order that the army march into Ukraine , the King himself parted ... to Warsaw to celebrate his victories over the Cossacks . " Later that year , on 14 August , Wiśniowiecki suddenly fell ill while in a camp near the village of Pawołocz , and died on August 20 , 1651 , at the age of only 39 . His cause of death was never known , while some ( even contemporaries ) speculated he was poisoned , but no conclusive evidence to support such a claim have ever been found . Based on sparse descriptions of his illness and subsequent investigations , some medical historians suggest the cause of death might have been a disease related to cholera . However , one account states , " following a cheerful conversation with other officers who had congregated for a military council in his tent on Sunday , 13 August N.S. he had eaten some cucumbers with zest and washed them down with mead , and from that contracted dysentery . After lying ill for a week , he died there , at Pavoloch " . He was given a " ceremonial funeral with the entire army present . On August 22 , Wiśniowiecki 's body was seen off with the utmost pomp on its journey to his residence " . 
 The truce of Zborov did not last long , and in the spring of 1651 Khmelnytsky <a href='null_genetive' title='1'><mark>'s</mark></a>Cossacks begun advancing west again . On June 1 , 1651 Wiśniowiecki brought his private army to face the Cossacks in Sokal . He commanded the left wing of the Polish @-@ Lithuanian army in the victorious Battle of Berestechko on 28 – 30 June . The Polish @-@ Lithuanian army advanced after the retreating Cossacks , but on July 17 the King " left the whole army to Potocki ... and <a href='been_done' title='2'><mark>having</mark></a> given the order that the army march into Ukraine , the King himself parted ... to Warsaw to celebrate his victories over the Cossacks . " Later that year , on 14 August , Wiśniowiecki suddenly<a href='been_done' title='3'><mark></mark></a> fell ill while in a camp near the village of Pawołocz , and died on August 20 , 1651 , at the age of only 39 . His cause of death was never known , while some ( even contemporaries ) speculated he was poisoned , but no conclusive evidence to support such a claim <a href='been_done' title='4'><mark>have</mark></a> ever been found . Based on sparse descriptions of his illness and subsequent investigations , some medical historians suggest the cause of death might have been a disease related to cholera . However , one account states , " following a cheerful conversation with other officers <a href='null_relcl' title='5'><mark>who</mark></a><a href='been_done' title='6'><mark>had</mark></a> congregated for a military council in his tent on Sunday , 13 August N.S. he <a href='been_done' title='7'><mark>had</mark></a> eaten some cucumbers with zest and washed them down with mead , and from that contracted dysentery . After lying ill for a week , he died there , at Pavoloch " . He was given a " ceremonial funeral with the entire army present . On August 22 , Wiśniowiecki <a href='null_genetive' title='8'><mark>'s</mark></a>body was seen off with the utmost pomp on its journey to his residence " . 
The truce of Zborov did not last long , and in da spring of 1651 Khmelnytsky  Cossacks begun advancing west again . On June 1 , 1651 Wiśniowiecki brought his private army to face tdaCossacks in Sokal . He commanded the left wing of the Polish @-@ Lithuanian army in the victorious Battle of Berestechko on 28 – 30 June . Thdaolish @-@ Lithuanian army advanced after thedatreating Cossacks , but on July 17 the King " left the dale army to Potocki ... and done given the odar that the army march into Ukraine , the King himself parted ... to Warsaw to celebrate his victories ova the Cossacks . " Later that year , on 14 August , Wiśniowiecki suddenly done fell ill while in a camp near the vidage of Pawołocz , and died on August 20 , 1651 , at the age of only 39 . His cuz of death was never known , while sum ( even contemporaries ) speculated he was poisoned , but no conclusive evidence to support such a claim done ever been found . Based on sparse descriptions of his illness and subsequent investigations , ssummedical historians suggest the cacda death might have been a disease related to cholera . However , one account states , " following a cheerful conversation with other officers done congregated for a military council in his tent on Sunday , 13 August N.S. he done eaten some cucumbers wid zest and washed them down wwittmead , and from dat contracted dysentery . After lien ill for a week , he died dere , at Pavoloch " . He was given a " ceremonial funeral with the entire army present . On August 22 , Wiśniowiecki  body was seen offf wwidthe utmost pomp on its journey to his residence " .