Thomas Phelippes (1556–1625), also known asThomas Phillips was alinguist, who was employed as aforger andintelligence gatherer. He served mainly under SirFrancis Walsingham, in the time ofElizabeth I, and most notably deciphered the coded letters ofBabington Plot conspirators.

Little is known about Phelippes family background except that he was the son of a cloth merchant. Despite his humble origins, it is believed that he enteredTrinity College, Cambridge, in 1569 and graduated with aBachelor of Arts in 1574. Phelippes was a linguist who could speak French, Italian, Spanish, Latin and German. His education helped him to master cipher skills and be an excellentcryptographer of high reputation. Therefore, he was employed by SirFrancis Walsingham, the principal secretary to Queen Elizabeth I.

Phelippes joined the embassy ofAmias Paulet in Paris in 1578. Another codeworker in diplomatic circles at this times wasJohn Somers (died 1585).^[1] The appearance of Phelippes in 1586 was described byMary, Queen of Scots, 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 short-sighted.^[2] Later in life his eyesight weakened and he was helped in his work by his wife, Mary.^[3] He has been described as "an excellent linguist, and, above all, a person with a positive genius for deciphering letters."^[4]

Phelippes is most remembered for his postscript to the "bloody letter" sent by Mary, Queen of Scots, toAnthony Babington regarding the Babington plot. When he sentWalsingham the letter provingMary, Queen of Scots's complicity in the plot Phelippes had drawn a gallows on the envelope. According to historian Neville Williams,^[5] the notes were smuggled to Mary via empty barrels from a brewer inBurton upon Trent who supplied the house atChartley Manor where she was being held prisoner in the custody of SirAmias Paulet. Phelippes was kept busy with a backlog of correspondence requested by Her Majesty whose letters contained day to day matters as well as those of a more sensitive type. Walsingham had to wait a whole seven months before he got what he wanted. This postscript asked Babington for the names of the plotters involved in the planned assassination ofQueen Elizabeth I, and henceFrancis Walsingham was able to prove Mary's direct involvement in the plot, and have her executed.^[6][7]

Phelippes questioned Mary's secretaries and a servantJérôme Pasquier in theTower of London. In September 1586, Pasquier confessed to writing a letters incipher for Mary.^[8] Pasquier recalled a letter for the French ambassadorMichel de Castelnau, asking him to negotiate a pardon forFrancis Throckmorton who was executed in 1584 for his part in theThrockmorton Plot.^[9]

• The codebreakers, the comprehensive history of secret communication from ancient times to the internet (revised and updated 1996) – David KahnISBN 0-684-83130-9
• Cryptology and statecraft in the Dutch Republic – Karl de LeeuwISBN 90-5776-039-8
• Spies & spymasters, a concise history of intelligence –Jock HaswellISBN 0-500-01178-8
• The Watchers, a secret history of the reign of Elizabeth I – Stephen AlfordISBN 978-0-141-04365-4

• British cryptographers
• 1556 births
• 1625 deaths
• Political forgery
• Throckmorton Plot
• Babington Plot
• 16th-century English people
• 17th-century English people
• 16th-century cryptographers
• Alumni of Trinity College, Cambridge

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