Agnes von Mansfeld - Eisleben Agnes von Mansfeld - Eisleben ( 1551 – 1637 ) was Countess of Mansfeld and the daughter of Johann ( Hans ) Georg I , of Mansfeld Eisleben . She converted Gebhard , Seneschal of Waldburg , the Prince - Elector of Electorate of Cologne and archbishop of the Diocese of Cologne to the Protestant faith , leading to the Cologne War ( 1583 – 1588 ) . After a multiple year odyssey in which she and her husband sought refuge in several parts of northern Germany , Gebhard relinquished his claim on the Electorate . They settled in Strassbourg , where he had retained a position in the Cathedral chapter . After his death in 1601 , she came under the protection of the Duke of Wūrttemberg , who had himself been chased from his duchy . She died in 1637 . Affair . Agnes was the daughter of Johann ( Hans ) Georg I , of Mansfeld Eisleben ( 1515 14 August 1579 ) , and his wife , Katharina of Mansfeld - Hinterort ( 1521 / 1525 1580 / 1583 ) . Although born and raised in the town of Mansfeld , in Saxony , as an adult , Agnes von Mansfeld Eisleben became a Protestant canoness at a cloister in Gerresheim , today a district of Düsseldorf . Agnes ' sister Sibilla lived in the city of Cologne , having married to the " Freiherr " ( baron ) Peter von Kriechingen ; although a member of the cloister , Agnes was not bound to it and was free during her days to move about the city . She visited Sibilla one day , and was noticed by the Elector of Cologne , Gebhard , Truchsess von Waldburg . Reportedly a beautiful woman ( she was also known as the lovely Mansfeld girl ) he sought her out , and they started a liaison . Two of her brothers , Hoyer and Ernst , visited Gebhard at the archbishop ' s palace in the electoral capital of Bonn , and convinced him to marry her . She insisted Gebhard first convert to Calvinism . The difficulties of a conversion by a Catholic Archbishop and Prince - elector of the Holy Roman Empire had been faced before : Hermann von Wied had also converted to Protestantism , and had resigned from his office . Similarly , Gebhard ' s immediate predecessor , Salentin IX of Isenburg - Grenzau had resigned to marry when it appeared his family line would become extinct . Initially , it appeared that Gebhard would resign . However , several of his associates in the Cathedral chapter convinced him that he could have the lady " and " the Electorate . Before Christmas in 1582 , he proclaimed the Reformation from the pulpit in Cologne , establishing Protestantism on parity with Catholicism in the archdiocese . This declaration of parity between Protestantism and Catholics in an electoral territory contravened the Religious Peace of Augsburg established in 1555 . In this document , to which the all the Estates of the Holy Roman Empire agreed , confirmed the co - existence of Lutheranism and Catholicism in select polities were both religious were already established ; in all other regions , the principle of Cuius regio , eius religio ( loosely translated from Latin as " Whose realm , his religion " ) confirmed the religion of the reigning sovereign to be the religion of his subjects . Unlikely match . Gebhard ' s conversion under the influence of Agnes caused more than a ripple of scandal in the aristocratic circles of the Holy Roman Empire . Descended as he was from the hereditary seneschal s of Waldburg , Gebhard came from a line of stalwart Catholic defenders of what was considered the universal faith . One of his uncles was the bishop of Augsburg ; his grandfather ' s brother had been a general in the German Peasants ' War of 1525 and instrumental in the destruction of the German Peasant army . The family had been long - time supporters of Habsburg dynastic aspirations and policies , and key advisers for in the often - troubled Imperial relationships with the Swabian Imperial circle ( " Kreis " ) . Gebhard himself had been raised in a Catholic tradition , and strongly influenced by the Jesuits in his education . His career had been solely focused on obtaining a preferential position in the ecclesiastical hierarchy , and his election as the archbishop of Cologne , in a close contest with the equally - qualified Wittelsbach candidate , attested not to the diligence and application of his personal faith , but his family ' s Imperial influence . On the other side of the relationship , Agnes came from a family of dedicated Lutherans ; the town in which she was born and raised , and whose name she bore , Eisleben , was also Martin Luther ' s home town . Her father and her uncles had been signatories of the Book of Concord , established in 1580 as the doctrinal standard of the Lutheran faith . Luther himself had negotiated a settlement to a disagreement between her uncles and her brothers over inheritance and succession issues . Her placement in the religious community at Gerresheim was a factor of her nobility and her family ' s connections ; although she came from the impoverished side of the old Mansfeld house , her family continued to wield influence in Imperial , Saxon , and religious circles , although it is unclear why she was placed in a Calvinist convent . The marriage of this seeming unlikely pair caused a scandal throughout the Empire . At 27 - years - of - age , Gebhard had apparently abjured the matrimonial life in his acceptance of the church career often reserved for a second or third son of noble families . If he had converted to Lutheranism and resigned from his electoral and episcopal responsibilities , the marriage might have made a ripple in social circles , but his refusal to give up his electoral and episcopal responsibilities , his declaration of the electorate as henceforth a dynastic property , however , made his marriage of utmost political importance . Furthermore , his conversion to Calvinism was heresy , because Calvinism was not one of the two legal professions of faith accepted by the Peace of Augsburg in 1556 . War . News of the pending marriage became public in late November 1582 , but it was still unclear what Gebhard would do . Precedent suggested he would resign prior to his marriage , but rumors abounded that he would convert the Electorate to Protestantism , perhaps forcibly . Throughout the Electorate , and on its borders , his supporters and opponents gathered their troops , armed their garrisons , stockpiled food , and prepared for war . On 19 December 1582 , Gebhard announced his conversion , from , as he phrased it , the " darkness of the papacy to the Light " of the Word of God . His proclamation of the Reformation from the Cathedral pulpit in the Imperial City of Cologne established Calvinism as a religious option in the Electorate . He also intended to convert the electorate into a dynastic property generated an uproar among the other Prince - electors . The transformation of an important ecclesiastical territory into a secular , dynastic duchy would then bring the principle of " cuius regio , eius religio " into play in the Electorate . Under this principle , all of Gebhard ' s subjects would be required to convert to his faith : " his rule , his religion " . The conversion of the Archbishop of Cologne to Protestantism also triggered religious and political repercussions throughout the Holy Roman Empire . Gebhard ' s conversion had widespread implications for the future of the Holy Roman Empire ' s electoral process , established by the Golden Bull of 1356 . The council continued for more than a year , and eventually moved to other cities ; although several times they seemed close to negotiating a conclusion to the crisis , a successful agreement remained beyond their reach . They also offered Gebhard a sum of money to relinquish his claim , which he refused on the high moral grounds of religious principle . Agnes and Gebhard married on 2 February 1583 in Bonn and retired to the Elector ' s country seat in Poppelsdorf to celebrate their nuptials . Within weeks , the Cathedral chapter had deposed Gebhard , electing in his place an old opponent , Ernst of Bavaria , the brother of Wilhelm V , Duke of Bavaria , who immediately set about raising an army with the help of his brother the duke , and his second brother , Ferdinand of Bavaria . In the spring and summer , Agnes and Gebhard did likewise , traveling to different parts of the electorate , raising an army , and extending the Protestant cause . By October , Ernst ' s brother Ferdinand entered the electorate from the south , near Koblenz . In their northward progress , they left a path of fire and destruction . Agnes and Gebhard fled , as Poppelsdorf , then Godesberg , and later the capital city of the electorate , Bonn , were over - run and destroyed . Initially , the couple fled to Vest Recklinghausen , a fiefdom of the Electorate . There , Agnes and Gebhard encouraged an outbreak of iconoclasm that destroyed many well - known and beloved religious sites ; the Reformation had already been wrought in Vest and Recklinghausen , and many of the inhabitants had converted to the new faith . The burst of iconoclastic energy , indulged predominantly by Gebhard ' s troops and not by the inhabitants themselves , alienated the residents from Gebhard , his wife , and their cause . With local support , Catholic armies chased the couple from Vest Recklinghausen later in the year . Gebhard and Agnes escaped with approximately 1000 cavalry and some infantry . A multiple year odyssey followed , as Agnes and her husband sought refuge in the northern territories of the Electorate at the castle Arensberg , and later at the city of Delft , with William I of Orange . Living in the Netherlands , they became acquainted with Elizabeth ' s envoy , Robert Dudley , 1st Earl of Leicester , and entered into lengthy negotiations with Elizabeth ' s Court to obtain support for Gebhard ' s cause ; these efforts failed to garner assistance for renewing the war either from the English queen or in any other quarter . In 1585 , Agnes reportedly traveled to England in a futile effort to seek assistance from Elizabeth I , but this claim has been refuted by modern scholars . After his once prosperous electorate was ruined by war , Gebhard relinquished his claim on it in 1588 . Ernst of Bavaria , had recruited the assistance of Alexander Farnese , Duke of Parma . By some twist of fate , her first cousin , Karl von Mansfeld , was in the service of the Duke of Parma at the Destruction of Neuss , a critical battle that turned the tide of war against her husband . Peace in Strassbourg . In 1589 , they could not return to the Electorate territories , which her husband had relinquished , nor could she , a married lady , return to the convent at Gerresheim . They sought refuge in Strassbourg , a stronghold of Calvinism . Gebhard had been a member of the Cathedral Chapter there since 1576 . Three other canons from Cologne had also taken refuge in Strassbourg after 1583 . Shortly after their marriage in 1583 , Gebhard had written his " Testament " in which he left his estate to his brother , Karl , and a life - time annuity to Agnes , and charged Karl with her safety and protection . Karl died on 18 June 1593 , and was buried in the Strasbourg cathedral ; Gebhard wrote a codicil leaving Agnes to the care and protection of the Dukes of Württemberg . Gebhard died in 21 May 1601 . Until her death in 1637 , she lived under the protection of the Dukes , first Friedrich I , later Johann Friedrich and then his son Eberhard . She was buried in Sulzbach . Cultural References . The life of Agnes and her romantic union with Gebhard became a theme for diverse story tellers and novelists , and is today still a resource of historical novelists . Genealogy . Father : Johann Georg I of Mansfeld - Eisleben Mother : Katharina of Mansfeld - Hinterort Children :