The Neue Deutsche Biographie, drawing on twentieth-century scholarship concerning the correspondence, describes their relationship as a genuine and intense affair beginning around 1690 and treats substantial portions of the surviving letters as authentic evidence of their relationship.
Leibniz University Hannover likewise describes Sophia Dorothea’s passionate correspondence with Königsmarck and notes that coded references were used for figures at the Hanoverian court.
This matters because the Königsmarck mystery is sometimes told as though the romance itself were merely a later legend.
The surviving evidence makes that difficult to maintain.
There was a dangerous relationship.
There were passionate letters.
And by 1694, the situation had moved beyond secret correspondence.
Sophia Dorothea wanted to escape.
They Were Preparing to Leave
By the summer of 1694, Sophia Dorothea and Königsmarck were considering a plan that could turn a private scandal into a dynastic catastrophe.
They intended to get away from Hanover.
Königsmarck was preparing to enter Saxon service. Sophia Dorothea was seeking release from her marriage.
Modern German biographical scholarship states that Königsmarck had been appointed a general by Augustus the Strong and was preparing to flee Hanover with Sophia Dorothea as she pursued a separation from her husband.
That changed the stakes dramatically.
A miserable princess conducting a secret affair was embarrassing.
The wife of Hanover’s heir attempting to flee with another man was politically explosive.
Sophia Dorothea was not an obscure noblewoman.
She was the mother of Georg Ludwig’s legitimate heirs.
She was the daughter and heiress of the Duke of Celle.
Her behavior therefore touched dynastic alliances, property, inheritance and the reputation of a ruling house whose importance in Europe was increasing.
The Hanoverian court could not treat the matter as an ordinary marital quarrel.
And sometime in July 1694, the court appears to have learned enough about what was happening to act.
Then Königsmarck went to the palace.
The Last Night
The exact chronology can be confusing because historical accounts sometimes use different calendar systems and dates.
The modern Neue Deutsche Biographie places Königsmarck’s killing during the night of July 11–12, 1694.
What followed became one of the great mysteries attached to the early Hanoverian dynasty.
Königsmarck entered the Leine Palace.
He did not return.
There was no ordinary announcement that he had been arrested.
There was no public prosecution.
There was no execution announced by the state.
There was no body presented to his family.
He simply ceased to appear.
For Königsmarck’s relatives, this created a practical as well as emotional nightmare.
His sister Aurora von Königsmarck began trying to discover what had happened to him. According to her German biographical record, she traveled to Dresden in the autumn of 1694 after unsuccessful attempts elsewhere to obtain help. She hoped that the Elector of Saxony—into whose service her brother had been entering—might either help rescue him if he remained alive or establish that he was dead.
Even inheritance became difficult because his family lacked certainty about his fate.
The Hanoverian court, meanwhile, did not provide a transparent explanation.
Rumors filled the vacuum.
And the most persistent rumor was murder.