Most are annotated on the dorse in a contemporary hand (likely Charles Prescot (CP) himself) with the correspondent’s name and date of letter. Many also are endorsed by his son Charles Kenrick Prescot (CKP) with brief notes on the letter’s content, often ending with ‘KTL’ (kai ta loipa, 'and the other things') in mixed Greek and Latin letters.

For years in which the Rev'd Dr Kenrick Prescot was still alive, where the salutation is simply, e.g., ‘Sir' or 'Prescot', it may be safely assumed that the addressee is indeed CP when the letter’s direction is to 'Mr' or 'The Rev'd Mr' Prescot.