Excerpts of Nicholas Throckmorton's Cipher Letters (1559)

 BL Add MS 4136 includes many papers related to Nichlas Throckmorton. Sheets after sheets are filled with numbered segments in cipher. I found many of them can be read with a key reconstructed from Add MS 35830. Although the papers from Add MS 4136 are annotated with the dates and the writer (Nicholas Throckmorton, ambassador in France, and his successors), the letters calendared in CSP foreign did not seem to quite match.
When I deciphered a sequence "marques d'Alboeuf and Martigues" in one letter, it allowed me to find the decipherment of full letters printed in Forbes (1740), the source of CSP. It confirmed that the cipher segments in Add MS 4136 are excerpts corresponding to the text in italics (i.e., those portions in cipher) in Forbes (1740).
I'm still working on this. Hopefully, I can report the results in near future.

By the way, Nicholas Throckmorton's cipher seems to have a fairly large number of code symbols. Often, a symbol consists of the initial letter of the word it represents and some additional stroke.