Erik Larsson Sparre (born Erik Larsson; also known as Erik Gyllensparre, Eric Sparre, or Erik Sparre of Rossvik; 13 July 1550 – 20 March 1600) was a Swedish noble, statesman, diplomat, and political theorist. He served as Privy Councilor from 1575 or 1576 until 1590 and Lord High Chancellor of Sweden from 1593 until his execution in 1600.

An esteemed orator and rhetorician, Sparre was considered the spokesman for the well-organized aristocratic opposition who advocated for parliamentary sovereignty in the Swedish government and is largely remembered for his contributions to Swedish law. His major written work ('For the Law, the King, and the Masses')remains highly-regarded as an early defense of contractualism and earned him a reputation as the "father of Swedish constitutional law". Sparre's ideas were initially backed by John III of Sweden in order to check the ambitions of John's brother, Duke Charles, but relations between Sparre and John soured when the nobility was able to overrule the king's prerogative during a stand-off in Reval (modern-day Tallinn, Estonia).

Sparre's diplomatic career was long and varied. He had early successes negotiating with the Danes in border disputes and helped to secure Sigismund III Vasa's accession to the Polish throne. During the discussions of Sigismund's election, Polish and Swedish tensions heightened after a misunderstanding about the annexation of Estonia, a fault that was blamed on Sparre. Following the death of John in 1592, Sparre backed Sigismund's attempt to secure the Swedish crown from Charles, but failed to secure significant material support from potential allies abroad. After Sigismund's defeat, Sparre was convicted of treason during a show trial and beheaded during the Linköping Bloodbath.

Early life Erik Larsson was born on 13 July 1550 to of the noble family Sparre and Britta Turesdotter of the noble family Trolle. Lars was well-regarded, holding a strong reputation and friendship with King Gustav I, serving as his top general. Records of Erik's youth are scarce and often contradictory, but it is likely that he studied abroad between 1569 and 1573; a 1570 record at the University of Frankfurt an der Oder lists a student as ('Erik Sparre, noble, Swede'). He likely furthered his education in Padua, Italy. During his time abroad, Sparre developed exceptionally strong language skills, particularly in Italian and Latin, though he was conversant in French as well. At some point in 1574, he returned to Sweden. On 30 November of the same year, he proposed to Ebbe Brahe, daughter of Per Brahe the Elder; Per was first cousin to John III of Sweden and a highly-influential figure in the Swedish court.

In 1575 or 1576, Sparre was appointed Privy Councilor () and had a special interest in the organization of the National Archives. Largely uninvolved in the everyday operations of the office, he was used by the court as a functionary and diplomat. He was effectively utilized as commissioner of negotiations with the Danes in March 1575 regarding the Swedish–Danish border before later being dispatched to the courts of the Count of East Frisia and the Holy Roman Emperor in the summer of the same year. Despite these early successes, Sparre was party to several power struggles between the Crown of Sweden, the Duke, and the high nobility, particularly with regards to the distribution of power. In March 1576, Sparre and other members of the nobility submitted new proposals for the liturgy on behalf of the king and the appointment of higher officials to Duke Charles, which he rejected. On 11 February 1577, Sparre, Brahe the Elder, and two other nobles from Uppland met in Stockholm with the clergy and the king, which affirmed the previous liturgical changes and drew Sparre in the middle of the power struggle between the king and the duke.

Sparre married Ebbe Brahe in 1578 at a house owned by Catherine Stenbock, the dowager queen, on Svartmangatan in Stockholm. John and his first wife, Catherine Jagellonica, were present as guests for three days, while Catherine Stenbock – along with the Margravine of Baden and the Duchess of Mecklenburg – stayed for four or five days; both the margravine and the duchess were cousins of the king. In August 1580, Sparre served as commissioner for another meeting with the Danes in Knäred and, the following year, he and Hogenskild Bielke traveled to the Duchy of Mecklenburg to negotiate a marriage between the king's sister, Elizabeth, and Duke Christopher of Mecklenburg.

In 1582, Sparre was made of Västmanland, Bergslagen, and Dalarna. On 1 March of the following year, one of John's officials, a Scotsman named Andrew Keith, honored Sparre with the title of baron. Despite the honor, Sparre claimed never to have requested the title nor petitioned the king to have it recognized as legitimate.

Sparre is considered one of the most learned men of his time, particularly in Sweden. He kept correspondence with many well-known scientists and historians of the era, such as the Danish astronomer Tycho Brahe, and served as one of the Rostock historian David Chytraeus's patrons in Sweden. Sparre's patronage included part of the printing costs of the latter's work, namely his history of the Nordic countries, ('The Chronicle of Saxony and [Those] Near the Arctic World'), published in 1590.

Sparre was a strong advocate for legislative primacy in Sweden, arguing that the Privy Council of Sweden held a special place in society as the "keystone" of the legal system. Sparre's best-known work is his pamphlet ('For the Law, the King, and the Masses'). The date of its publication is of some debate; it is generally accepted that Sparre wrote the in 1582, though most sources cite its publication in either 1585 or a more vague "the 1580s". Some sources estimate the date of publication as late as 1586 or 1587.

In the pamphlet, Sparre wrote that the duke was beholden to the laws of the nation and had no sovereign authority; wherever the rights and duties of the Crown interfered, ducal rights were to be subordinated. Sparre further sought to distinguish the office and rights of the king from the office and rights of the Crown, arguing that the possessions of which were not to be minimized in any way, irrespective of any circumstance or sovereign. He argued that the Crown and the king had disparate natures; the king, who is mortal, should not be able to infringe upon the rights and duties of the immutable Crown, which is immortal. Thus, royal titles were issued by the eternal political force of the Crown which could not be trod upon by any mortal king; stately institutions andmost importantlythe nobility were therefore an extension of the immortal Crown. However, dukes served simply as a , an extension of the rights and privileges of the king without the same claims to sovereignty, which applied only to "accidents and conveniences" (). Consent of the Estates, particularly the "leading Estates", was the cornerstone of the legal process, which bound "all Swedes, present and absent, those who swear and those who do not swear, those born and unborn" to rights and duties. Under the law, the king, as a mortal Swede, was himself beholden to it; the supremacy of law applied to all kings irrespective of their hereditary or elected claims of absolutism. The work is lauded as an early appeal to contractualism and orthodox ideas of constitutional doctrine, comparable to the works of Jean Bodin and James Madison. The success of Sparre's rhetoric, which advocated for common welfare and navigated the differing class interests of the era, has led historians to refer to Sparre as "the father of Swedish constitutional law" and "the father of Swedish constitutionalism".

Sparre stated that he wrote the pamphlet at John's request and historians believe this was likely true; John sought to limit Charles's ambition to concentrate power and saw a strong anti-absolutist nobility as a means to that end. For John at the time, it appears that the risk of usurpation by Charles was of more concern than a conglomeration of power in the legislature. The work was also influenced significantly by Sparre's father-in-law, Per Brahe the Elder, who himself had quarrels with Charles and shared the ideas and sympathies of both Sparre and Hogenskild Bielke, especially in being concerned about the loss of privileges by the nobility and holding a sympathetic view of the Catholic Church.

Sparre is commonly associated with Bielke's political thought. Both held the high nobility as key to the future of Swedish law and sought to use their knowledge of history and law to further that end. The primary difference between them is the source of their jurisprudence; Bielke's sourcing and arguments tended to stem from a pragmatic, German-based legal system, while Sparre's tended to appeal to Roman and contemporary Italian law, citing both the and the – among others – in the . Together, Bielke and Sparre had drafted a statute on 27 January 1582 in the Riksdag that interpreted the law decisively against Charles, forbidding him from nominating bishops without the king's consent, trying nobles accused of serious crimes, expanding taxes other than agreed upon for the kingdom, restricting the privileges of the nobles, and much more, though its stipulations were largely ignored.

Mission to Poland

In April and May 1587, Sparre, Hogenskild Bielke, , and were invited to develop a plan of governance in the event John's son Sigismund III Vasa were elected King of the Polish–Lithuanian Commonwealth and inherited the throne of his father, making him king in both realms. In August, Sparre and his brother-in-law Erik Brahe were dispatched to the Commonwealth to act as Sigismund's agents. The discussion continued through the summer, but the agreementnow known as the ( or )was signed and sealed by John and Sigismund on 5 September. The Statute provided sweeping guarantees to Sweden's independence, secured a prohibition against Polish interference, and unequivocally defined Estonia as "a Swedish province". Sparre contributed to it significantly, though John was responsible for the final draft, as Sparre was not actually present in Kalmar when it was signed and sealed.

Despite the preparation, Sigismund's accession was not clearly secure until January 1588. During the course of negotiations with the Commonwealth, the Poles insisted that lands conquered by the Swedes in Estonia should be handed over to the Commonwealth. Sparre and Brahe were expressly forbidden from accepting any deal that required the surrender of Estonia into Polish hands. A well-regarded orator and rhetorician, Sparre was able to cinch the election of Sigismund without explicitly promising Estonia, butaccording to Johnwhen the was signed, Sparre made verbal promises "in excess of his instructions". These promises were later rescinded from the official compact after negotiations between John and Sigismund, the latter declaring at his coronation that Sweden would never be forced to cede any territory to the Commonwealth, though Sparre continued to be blamed for being willing to sacrifice Estonia for the rest of his life.

Conflict in Reval and charges of treason