'Ever thine. Ever mine. Ever ours.' Two centuries later, historians still haven't agreed on the identity of the woman who inspired the composer's famed lines.

It’s one of the greatest unsolved mysteries in musical history. Who was the woman who so besotted Ludwig van Beethoven that he was compelled to pen an infamously passionate and fervid love letter that has stood the test of time? The identity of Beethoven’s “Immortal Beloved” (more accurately translated as “Eternally Beloved”) has confounded historians for two centuries, and even inspired a movie. But the truth may never be known for certain.

The letter may never have been sent

Following Beethoven’s death in March 1827, his assistant, Anton Schindler, discovered a hidden drawer, which contained some pictures, money and two documents. One was a letter, written to his brothers in 1802 and later known as the Heiligenstadt Testament, in which Beethoven lamented his increasing deafness and wrote of his despair and depression over the impact the infirmity would have on his musical abilities.

The other was a letter, written in pencil in Beethoven’s uneven scrawl over 10 small pages. Composed in three bursts, it reveals his emotional torment and desire for an unnamed woman. He longs for them to be together, proposing an assignation at a nearby location known only as “K,” which historians believe was likely Karlsbad, now the Czech town of Karlovy Vary. Beethoven’s hopes for the relationship seem to darken as he writes. The last section conveys his resignation that their great love was never to be—as he signs off with the lines, “Ever thine. Ever mine. Ever ours.” The doomed affair coincided with the start of one of the darkest periods in Beethoven’s life, during which he failed to compose a major work for several years.

Many historians believe the letter was never actually sent, while others believe Beethoven may have sent a copy of the letter, while holding on to the original. Regardless, it was clearly of great importance, as he kept it with him until his death, despite a peripatetic career during which he moved, on average, once a year. Early scholars trying to solve the riddle were stymied because while the letter is dated July 6 and 7, no year was included, making it hard to piece together when in his life it was written. It was only in the 1950s that watermarks and other visual clues allowed a more definitive dating of 1812.

A number of women have been put forward as possible candidates

Beethoven’s romantic life was rocky, and he never married. He developed a series of romantic attachments, which may have remained unrequited and unconsummated. Despite his musical success, his relatively modest social background meant his frequent pursuits of well-born women were ultimately futile.

A piano pupil of Beethoven’s, Dorothea von Ertmann, has been cited as a possible contender, but although he dedicated a sonata to her, their relationship seems to have been non-romantic. Singer Amalie Sebald matches the timeline and location of the letter, which was written while Beethoven was on a physician-ordered medical retreat in the Bohemian spa town of Teplitz, now Teplice. Sebald and Beethoven were both in Teplitz in the summer of 1812, but his known letters to her also seem like those of a friend.

Arts patron Anna Marie Erdödy, a supporter and confidante of Beethoven’s, allowed the composer to live in her Vienna home for a period. She helped Beethoven gain a royal patronage, and the thankful composer dedicated several works to her. But arguments against Erdödy rest on geography. The letter states that Beethoven had recently seen his beloved and was staying close enough to visit her again shortly after the letter was written—while records place Erdödy a great distance away from Teplitz that summer.

Some historians have surmised that Beethoven fell deeply in love with Therese Malfatti, cousin to a close friend his, and even contemplated proposing in 1810. Once again, money got in the way. Her wealthy parents disapproved, and she was eventually married off to a nobleman. Many scholars believe his “Für Elise” was written in her honor.

Handwritten 'Immortal Beloved' letter from Beethoven

Beethoven's 'Immortal Beloved' letter, found in a secret drawer in his desk, ran 10 pages.

Two sisters and a cousin have been caught up in the debate

Julie “Giulietta” Guicciardi entered Beethoven’s life in the late 1790s. The wealthy daughter of noble parents, she began taking piano lessons with him in 1801, and he almost immediately fell in love with her. Her marriage to a count, who was also a composer, seemingly did little to dampen Beethoven’s ardor. He dedicated his famed “Moonlight Sonata” to Guicciardi, and reportedly later told Anton Schindler that she had been a great love. Schindler, in turn, named Guicciardi as the “Immortal Beloved” in his biography of Beethoven, but that idea has since been disputed, particularly because she seems to have disappeared from Beethoven’s life several years before the letter was written.

Among those casting doubt on Giulietta Guicciardi’s candidacy was her own cousin, Teréz Brunsvik. The Brunsvik family were members of the Hungarian nobility, and both she and her sister Josephine were students of Beethoven. Again, he seems to have quickly fallen for Josephine and remained close to her after her marriage. When she was widowed several years later, he pursued his case. Evidence of his feelings only came to light in the 1950s, when a Beethoven biographer published more than a dozen love letters written to Brunsvik.

Fearful that she would lose custody of her aristocratic-born children if she married a commoner, Brunsvik apparently rebuffed Beethoven. But after having a child out of wedlock, she did marry a commoner, with disastrous results. The ill-matched couple quarreled and quickly separated, prompting Teréz Brunsvik to write cryptically in her journal that Josephine would have been better off with Beethoven.

Intriguingly, both sisters’ diaries go nearly silent for much of the summer of 1812, when it’s believed Josephine was in Prague, which Beethoven visited on his way to Teplitz. Nine months after the “Beloved” letter was written, Brunsvik gave birth to a daughter, which some historians have theorized was Beethoven’s, although no definite proof exists. After years of financial and emotional turmoil, Brunsvik died in 1821.

Portrait of Antonie Brentano, possible inspiration for Beethoven's 'Immortal Beloved' letter

Antonie Brentano and her husband were close friends with Beethoven. The composer dedicated a new work

Another contender emerged in the 1970s

The daughter of an Austrian diplomat, Antonie “Toni” Brentano was deeply involved in the arts and became very close with Beethoven around 1810. She too was in Prague in early July 1812, before traveling to Karlsbad the same week Beethoven wrote the “Beloved” letter. (Beethoven arrived there two weeks later.)

Beethoven dedicated a new work to Brentano later that year, “An die Geliebte,” which can be translated as “To the Beloved.” The original score contains an inscription, believed to be in Brentano’s writing, in which she had asked Beethoven to compose it for her. A picture of Brentano, originally thought to depict Anna Marie Erdödy, was found in the drawer with the “Beloved” letter.

Skeptics, however, point out that unlike many of the other women in Beethoven’s life, Brentano was happily married—and was pregnant with her sixth child in the summer of 1812. Her husband was as close to Beethoven as she was, and both Brentanos remained friendly with Beethoven until his death. Beethoven may have been foolish when it came to love, but by all accounts, he was an exceedingly honorable man, leading many to doubt he would have carried on a passionate affair under his good friend’s nose.

The 'Immortal Beloved' film almost certainly got it wrong

The 1994 movie, starring Gary Oldman as Beethoven, won plaudits for its evocative and creative use of the composer’s music. But it greatly missed the mark, according to historians and scholars.

In the film, Beethoven’s assistant goes in search of the “Beloved” after finding the letter following Beethoven’s death. He discovers that the woman who’d stirred such passion was Beethoven’s sister-in-law, Johanna. The daughter of prosperous Viennese merchants, her affair with Beethoven leaves her pregnant. When he delays in marrying her, she marries his younger brother, Kaspar Anton Karl (commonly known as Karl). The movie depicts the tumultuous relationship between Beethoven and Johanna, and their unrequited love, with Johanna only able to read Beethoven’s searing love letter after his death.

Big screen swoon-worthy as the story was, it doesn’t square with the facts. Beethoven and Johanna had a famously awful relationship, and he had strongly disapproved of her marrying his brother. Her involvement and conviction in a subsequent embezzlement scheme—at almost the same time as the “Beloved” letter was written—almost certainly heightened Beethoven’s dislike.

When Karl developed tuberculosis just a few years after marrying Johanna, he initially dictated a will giving sole custody of his son, Karl, to Beethoven, not Johanna. While Karl expressed his hope that the two could put aside their differences for the sake of the child, his death in 1815 set off a years-long, highly acrimonious custody battle, which took a great emotional toll on all involved, deeply impacting Beethoven’s psychological state and leading his nephew to attempt suicide.