Thomas Phelippes

Early Life and Education

Thomas Phelippes was born in 1556, the son of a cloth merchant. Despite his relatively humble origins, he is believed to have entered Trinity College, Cambridge, in 1569, graduating with a Bachelor of Arts in 1574. He developed proficiency in French, Italian, Spanish, Latin, and German — a linguistic range that formed the foundation of his later career in cryptography and intelligence work. His education and aptitude led him to be described by contemporaries as "an excellent linguist, and, above all, a person with a positive genius for deciphering letters."

Career in Intelligence

Phelippes was employed by Sir Francis Walsingham, the principal secretary to Queen Elizabeth I, as a forger and intelligence gatherer. In 1578, he joined the embassy of Amias Paulet in Paris, where he worked alongside other codeworkers active in diplomatic circles, including John Somers, who died in 1585.

A physical description of Phelippes survives from 1586, provided by Mary, Queen of Scots herself, who characterized him as "a man of low stature, slender in every way, dark yellow-haired on the head and clear yellow bearded," with a pock-marked face and poor eyesight. As his vision deteriorated later in life, he was assisted in his work by his wife, Mary.

The Babington Plot

Phelippes is most closely associated with his pivotal role in exposing the Babington Plot, a conspiracy to assassinate Queen Elizabeth I and place Mary, Queen of Scots, on the English throne. Walsingham had arranged for Mary's correspondence to be smuggled in and out of Chartley Manor — where she was held prisoner under the custody of Sir Amias Paulet — via empty barrels supplied by a brewer from Burton upon Trent. This channel allowed Walsingham's agents to intercept, copy, and reseal Mary's letters without her knowledge.

Phelippes deciphered the coded letters passing between Mary and Anthony Babington, the plot's principal organizer. When he forwarded to Walsingham the letter that demonstrated Mary's complicity in the planned assassination, Phelippes marked the envelope with a drawing of a gallows — a signal that the evidence was sufficient to condemn her. Walsingham had waited seven months to obtain such proof.

Critically, Phelippes also composed a forged postscript appended to one of Mary's letters to Babington, requesting the names of the specific conspirators involved in the assassination scheme. This postscript helped Walsingham identify the plotters and build a comprehensive case against Mary, ultimately leading to her execution.

Following the unraveling of the plot, Phelippes interrogated Mary's secretaries and a servant named Jérôme Pasquier in the Tower of London. In September 1586, Pasquier confessed to having written letters in cipher on Mary's behalf, including one addressed to the French ambassador Michel de Castelnau seeking a pardon for Francis Throckmorton, who had been executed in 1584 for his role in the earlier Throckmorton Plot.

Legacy

Thomas Phelippes died in 1625. His work in cryptanalysis during the Elizabethan era represents one of the earliest documented applications of systematic codebreaking in English statecraft. His decipherment of the Babington correspondence remains a landmark episode in the history of intelligence and cryptography, demonstrating how the interception and analysis of coded communications could directly shape the course of political events.