Since most everyone but the lowest classes can read, letter writing is a popular social activity.
People send messages back and forth all day in all directions, whether around the mansion, to the house next door, across the city, or out to the countryside.
These are often brief notes, inquiring after health or inviting to dine, reminding the receiver of favors owed, or challenging them to a dog or cock fight. The language in these letters is usually more formal than the speaker would use in conversation, and is often quite over the top, full of blessings and humility.
Private letters will be sealed with wax, often stamped with the seal of the person sending it (if they are wealthy enough to have such a thing). Casual letters are usually just folded.
All relatively wealthy households have servants who may be asked to deliver a letter at any time. It is not unusual to see messengers running at top speed through the city, aided by the magic of a household mage.
Making Letters for Maps
To make letters sound more authentic, try the following:
To a relative: Good uncle, after my heartiest commendations to you and to mine aunt...
To a friend: After my very hearty commendations...
To a mother: My humble duty remembered...
To a nobleman: Right Worshipful, My humble duty remembered, hoping the Almighty Builder has given you health and prosperity which on my knees I beseech him to long continue...
To a noble relative: Your lordship's assured friend and kinsman (sig.)
To an equal who has done (or perhaps been asked) a favor: Thus indebted to you for your pains taken for me, I bid you farewell. Sprowston, this 12 of April. Your friend, (sig.)
To a friend: Thus I commit you to God's good protection. From Hampton Court the 2d of January. Your very assured friend (sig.)
To a parent: And thus with commendations from my partner and sister with thanks for our good cheer, and not forgetting Aunt Lettyce, with blessing to Mall, nephews Lewis, Harvey, and Nick, and Nan, with our humble duty to my mother we commit you to God this Saturday 17 December (sig.)
To a brother: I pray you remember my duty to my good mother. This with my kindest commend to you and my good sister, wishing you all happiness, I rest your loving sister (sig.)
To a kinsman: Your very assured loving friend and kinsman (sig.)
To a mother: With the remembrance of my humble duty unto you, I humbly take my leave and rest, Your dutiful and obedient son, (sig.)