6 Famous Historical Figures Who Maintained Secretly Coded Diaries

Throughout history, many people have documented their personal experiences in diaries, and some have gained fame primarily for their roles as diarists. What sets others apart, though, is their use of secret codes to conceal their private reflections. Below are some of the most renowned figures who encoded their journals with complex ciphers.

1. Beatrix Potter

The beloved children's author Beatrix Potter (1866–1943) is best remembered for her tales such as The Tale of Peter Rabbit. However, she also kept a series of coded diaries from the age of 15 to 30. Although Potter never revealed why she created the code, her biographer, Linda Lear, speculated that it was a response to her restrictive upbringing and a desire to express herself in secret more freely than she could in her daily life.

The codes she used would later prove to be extremely challenging for scholars to decipher. After Potter's death, Leslie Linder, a long-time admirer of her work, dedicated over five years to cracking the code with no success. However, Linder finally made a breakthrough when he noticed a reference to '1793' and the Roman numeral 'XVI,' which he connected to Louis XVI of France, who was executed in 1793. This realization led him to decode a nearby word as 'execution.' Once this clue was uncovered, Linder was able to unlock the rest of Potter's secret code relatively quickly. The deciphered diaries provided detailed accounts of her daily life, including transcriptions of conversations she overheard.

2. Franklin D. Roosevelt

Like all presidents, much of Franklin D. Roosevelt’s (1882–1945) life has been thoroughly documented. However, parts of his personal world remained a mystery, particularly sections of a private diary Roosevelt kept in his early twenties, which was written in a secret code.

In 1970, Dr. Nona Ferndon discovered Roosevelt’s coded diary and shared it with several cryptographers. She cracked the code by recognizing that Roosevelt had substituted certain letters with others. The decryption was confirmed in January 1972, revealing various personal details about his life and romantic interests.

3. Samuel Pepys

Samuel Pepys (1633–1703) is widely regarded as one of the most significant diarists in English literature, though his diaries remained private for over a century after his death. His detailed account of life in 17th-century London, including the 1665–1666 plague, has become an essential resource for historians. However, during his lifetime, the contents of his diaries were kept highly secret.

Pepys wrote his journal in a shorthand system created by the stenographer Thomas Shelton. To the untrained eye, the diary appeared as an enigmatic code, which allowed Pepys to keep his personal affairs concealed. He was so fond of using ciphers that he even invented some of his own for others to adopt. Pepys ceased writing in his diary as his eyesight began to fail, although he did not lose his sight as he had feared. The journal's contents were transcribed from the code into English in the early 19th century and were first published in 1825.

4. Charles Wesley

Charles Wesley (1707–1788), an English Methodist, is best known for writing thousands of hymns. However, he also authored another major work: his diaries, which spanned over 1000 manuscript pages and were written in a secret code that remained unsolved for 270 years.

Professor Kenneth Newport, who had previously worked on Wesley’s religious writings, eventually cracked the code in the diaries. Wesley had encoded four of the gospels in a similar cipher to the one used in his diaries. Newport spent nearly a decade transcribing the diaries, and with his expertise in the original gospels, he was finally able to decipher the meaning of the code.

Once the code was decoded, Charles Wesley’s diary revealed numerous insights into his relationship with his brother John, including their theological disagreements and Charles’s frustration when John broke their pact never to marry. The Wesley family was known for using codes; John also kept his own coded diary.

5. Ludwig Wittgenstein

The concept of a secret language, understood only by the creator, was an idea that philosopher Ludwig Wittgenstein (1889–1951) explored in his work. It was also something he personally experienced.

Ludwig Wittgenstein developed his own secret code for a diary he began keeping while serving in the Austrian Army during World War I. He started using the code in August 1914 to prevent other soldiers from reading his private thoughts. In the 1960s, the diary was deciphered by two of his literary executors, Georg Henrik von Wright and Elizabeth Anscombe, who discovered that Wittgenstein had reversed the letters of the alphabet to create his unique cipher.

6. Olga Romanov

Olga Romanov (1895–1918), the eldest daughter of Russia's last Tsar, Nicholas II, began keeping a diary in 1905 and continued it for over ten years. As a young woman, she used secret codes to protect her most intimate thoughts, especially when writing about her crushes. She often used initials instead of men's full names. Most notably, she used code when writing about her feelings for Pavel Voronov, the man she loved and dreamed of marrying, only to see him become engaged to someone else.

Olga Romanov stopped keeping her diary after her father’s abdication in 1917. The following year, she and her family were tragically murdered. After her death, her diaries, along with other family papers, were recovered and preserved, eventually becoming accessible to scholars. A researcher named Maria Zemlyanichenko noticed the frequent use of initials to refer to various people, which allowed her to deduce some of their identities. The diary was later translated into English by Helen Azar and published in 2013.