Question: Who was king of Sweden during the Battle of Kirchholm?

full_context: Document 1: Åbo Bloodbath: The Åbo Bloodbath of 10 November 1599 was a public execution in the Finnish town of Turku (Åbo), then part of the Kingdom of Sweden, in the context of the War against Sigismund and the Club War. Sweden was by then in the final phase of a civil war, with one faction supporting king Sigismund III Vasa, who also was king and Grand Duke of Poland-Lithuania, and another faction supporting duke Charles of Södermanland, the later Charles IX, Sigismund's paternal uncle. After winning the upper hand in the dispute, Charles crushed the last resistance to his rule, particularly in Finland, while Sigismund had already retreated to Poland.
Document 2: Russo-Polish War (1654–1667): The Russo-Polish War of 1654–1667, also called Thirteen Years' War, First Northern War, or the War for Ukraine, was a major conflict between Tsardom of Russia and the Polish-Lithuanian Commonwealth. Between 1655 and 1660, the Second Northern War was also fought in the Polish-Lithuanian Commonwealth, thus this period became known in Poland as "The Deluge". The Commonwealth initially suffered defeats, but regained its ground and won most of the battles. However its plundered economy was not able to fund the long conflict. Facing internal crisis and civil war, Poland was forced to sign a truce. The war ended with significant Russian territorial gains and marked the beginning of the rise of Russia as a great power in Eastern Europe.
Document 3: Polish hussars: The Polish Hussars ( , , or ; Polish: "Husaria" ), or Winged Hussars, were one of the main types of the cavalry in the Polish-Lithuanian Commonwealth between the 16th and 18th centuries. When this cavalry type was first introduced by Serbian and Hungarian mercenary horsemen at the beginning of the 16th century, they served as light cavalry banners in the Polish army; by the second half of the 16th century and after Stephen Báthory's reforms, hussars had been transformed into heavily armored shock cavalry. Until the reforms of the 1770s, the husaria banners were considered the elite of the Polish cavalry.
Document 4: Battle of Kirchholm: The Battle of Kircholm (27 September 1605, or 17 September in the Old Style calendar then in use in Protestant countries) was one of the major battles in the Polish–Swedish War. The battle was decided in 20 minutes by the devastating charge of Polish cavalry, the Winged Hussars. The battle ended in the decisive victory of the Polish-Lithuanian forces, and is remembered as one of the greatest triumphs of Commonwealth cavalry.
Document 5: Battle of Trzciana: The Battle of Trzciana (also known as Battle of Honigfelde or Battle on the Stuhmer Heide or Battle of Sztum) took place on 25 June 1629 (usually said to be 27th in the New Style calendar) and was one of the battles of the Polish-Swedish War (1626–1629) or Second Swedish-Polish War. The Polish forces were led by Crown Field Hetman Stanisław Koniecpolski and imperial troops under Hans Georg von Arnim-Boitzenburg, sent by emperor Ferdinand II to aid Sigismund III, met with troops commanded by Swedish King Gustav II Adolf, who supported the Protestant Lutherans of Germany and northern Europe. Gustav Adolf was almost killed or captured twice. Fighting in Prussia continued after the battle into July and August and ended with stalemate and finally a truce accepted by Sigismund III.
Document 6: Polish–Swedish wars: The Polish–Swedish Wars were a series of wars between the Polish–Lithuanian Commonwealth and Sweden. Broadly construed, the term refers to a series of wars between 1563 and 1721. More narrowly, it refers to particular wars between 1600 and 1629. These are the wars included under the broader use of the term:
Document 7: Military of the Swedish Empire: From 1611 to 1721, Sweden was a European great power, becoming a dominant faction in the quest for control of the Baltic Sea and a formidable military power. During this period, known as "Stormaktstiden" (Swedish: ""The Great Power Era"" ), the Swedish Empire held a territory more than twice the size of its modern borders and one of the most successful military forces at the time, proving itself on numerous occasions on battlefields such as Wallhof, Narva and Düna. The military of the Swedish empire is commonly (and wrongfully) recognized only as the Caroleans, which were in fact not in service until the late 17th century under Karl XI and his successor. The Swedish Empire and its modern military force was founded by Gustavus Adolphus, who inherited the throne in 1611 at age 17. He immediately reformed the common European military based on mercenaries to a professional national army. However, before completing his vision of conquering the Holy Roman Empire, the warrior king was killed in action in 1632. His daughter and successor did little to improve Sweden's military position and abdicated early, providing the Swedish Empire with a more warlike ruler. Karl X Gustav was only king for 5 years, but conquered large amounts of territory that still belong to Sweden today (including Blekinge, Bohuslän, Skåne and Halland). His son Karl XI would further strengthen the army by introducing the Caroleans, which were also used by Karl XII in the Great Northern War.
Document 8: Polish–Swedish War (1600–11): The Polish–Swedish War (1600–11) was a continuation of struggle between Sweden and Poland over control of Livonia and Estonia, as well as the dispute over the Swedish throne between Charles IX of Sweden and Sigismund III of Poland.
Document 9: Battle of Podhajce (1667): The Battle of Podhajce (October 6–16, 1667) was fought in the town of Podhajce in the Polish-Lithuanian Commonwealth (nowadays Pidhaitsi, western Ukraine), and the area surrounding it as part of the Polish-Tartar War and the Great Turkish War. The army of the Polish-Lithuanian Commonwealth under John III Sobieski, totaling around 9,000 men defeated Tatar and Cossack forces under Petro Doroshenko and Adil Giray, which totaled around 35,000 men.
Document 10: Battle of Gniew: The Battle of Gniew or the Battle of Mewe was fought during the Polish–Swedish War (1626–1629), between Sweden and the Polish–Lithuanian Commonwealth from 22 September with initial skirmishes, to the main battle of 1 October 1626. Both the Swedish and Polish army were commanded by their kings – Gustavus Adolphus of Sweden and Sigismund III Vasa. The battle ended with a victory for Sweden. However, Polish and Swedish armies had different objectives. Sigismund Vasa wanted to protect Gdańsk from besieging. Gustav had to protect Gniew, which was important for the prestige for his army.
Document 11: Sigismund III Vasa: Sigismund III Vasa (also known as "Sigismund III of Poland", Polish: "Zygmunt III Waza" , Swedish: "Sigismund" , Lithuanian: "Žygimantas Vaza" , English exonym: "Sigmund"; 20 June 1566 – 30 April 1632
Document 12: Military of the Polish–Lithuanian Commonwealth: The military of the Polish–Lithuanian Commonwealth evolved from the merger of the armies of the Kingdom of Poland and the Grand Duchy of Lithuania following the 1569 Union of Lublin, which formed the Polish–Lithuanian Commonwealth. The army was commanded by the Hetmans of the Polish–Lithuanian Commonwealth. The most unique formation of the army was the heavy cavalry in the form of the Polish winged hussars. The Polish–Lithuanian Commonwealth Navy never played a major role in the military structure, and ceased to exist in the mid-17th century.
Document 13: Battle of Berestechko: The Battle of Berestechko (Polish: "Bitwa pod Beresteczkiem" ; Ukrainian: Берестецька битва, Битва під Берестечком ) was fought between the Ukrainian Cossacks, led by Hetman Bohdan Khmelnytsky, aided by their Crimean Tatar allies, and a Polish army under King John II Casimir. It was a battle of a Cossack rebellion in Ukraine that took place in the years 1648–1657 after the expiration of a two-year truce. Fought from 28 to 30 June 1651, the battle took place in the province of Volhynia, on the hilly plain south of the Styr River. The Polish camp was on the river opposite Berestechko and faced south, towards the Cossack army about two kilometers away, whose right flank was against the River Pliashivka (Pliashova) and the Tatar army on their left flank. It was probably the largest European land battle of the 17th century.
Document 14: War of the Polish Succession (1587–88): The War of the Polish Succession or the Habsburg-Polish War took place from 1587 to 1588 over the election of monarch after the death of King of Poland and Grand Duke of Lithuania Stephen Báthory. The war was fought between factions of Sigismund III Vasa and Maximilian III, with Sigismund eventually being crowned King of Poland and Grand Duke of Lithuania. Two major battles of this conflict included the Siege of Kraków, in which Maximilian III failed to capture the capital of the Commonwealth, and the Battle of Byczyna, in which Maximilian was forced to surrender. Sigismund's victory was significantly the doing of Chancellor and Hetman Jan Zamoyski, who stood behind both the political intrigue and the military victories of this conflict.
Document 15: Battle of Stångebro: The Battle of Stångebro, or the Battle of Linköping, took place at Linköping, Sweden, on 25 September 1598 (O.S.) and effectively ended the personal union between Sweden and the Polish–Lithuanian Commonwealth, that had existed since 1592. In the battle, an army of c. 8 ,000–12,000 commanded by Duke Charles defeated a mixed force of c. 5,000–8,000 consisting of an invading army of mercenaries in the king's employ and diverse but poorly co-ordinated supporting Swedish noblemen's forces commanded by King of both Sweden and the Polish–Lithuanian Commonwealth Sigismund III Vasa, who was acting to maintain and restore his personal union against anti-Catholic forces in Lutheran Sweden. The Swedish kings general Constantin fought at the western bridge.
ground_truth: Charles IX