Elizabeth Stuart, Queen of Bohemia, tried a polyalphabetic cipher in her correspondence with Thomas Roe, as described in "Ciphers in Early Stuart England before the Civil War". It switches Caesar substitution tables between words or word fragments. The key in Arabic figure placed before the word (fragment) indicates the shift in the Caesar cipher (counting from the plaintext itself). Thus, when the key is 4, "a" is enciphered as "d".
This cipher is called "Key 1 Roe" in Nadine Akkerman (ed.), The Correspondence of Elizabeth Stuart, Queen of Bohemia, Volume II (2011), p.1062, according to which only the keys 4, 5, 6, and 7 were used (obviously because larger shifts would make the counting too cumbersome).
Nadine Akkerman and Pete Langman (2024), Spycraft: Tricks and Tools of the Dangerous Trade from Elizabeth I to the Restoration provides specific examples (p.388, n.134). A typical ciphertext is:
I have had newes from K.[Arundell] 50.[Emperor] 6nfzn.[hath] 4kmyhq4.[giuen-] 4lmp.[him] 5mnw[hir] last 4dkwzhu[agswer]
("K" and "50" are nomenclature elements.)
This short specimen includes two enciphering errors: "hir" should be "his" and "agswer" should be "answer". The first error is a simple counting error, while the latter error arose because counting was in the opposite direction. That is, for the plaintext letter N, the fourth letter afterward, Q, should be the ciphertext letter, instead of which the ciphertext actually includes K, the fourth letter forward.
Similar errors due to opposite shifting were made when "electorat" was enciphered as "4bobz5yswey" (p.387, n.132). Here, E is incorrectly enciphered as B (instead of H) and C is incorrectly rendered Z (instead of F).
Akkerman and Lagman considers this kind of errors suggests use of a cipher wheel. That is, this can be readily explained as "reading the plaintext on the inner wheel and the ciphertext on the outer, that is, the 'wrong' way around". (You can see this by switching the plaintext and ciphertext lines in the above image.)
I think, however, counting in the opposite direction is more likely. The fact that only four shifts (4, 5, 6, 7) were used seems to show that Elizabeth did not have a table or a wheel at hand when working on the cipher. She was counting for enciphering each letter.
