public branding in medieval times,is there a letter code that was used?

Answer 1

In those times most people (including most branders and most criminals) could not read or write so if there was a code it definitely was not very complicated or very alphabetical.

In 17th century England they branded vagabonds with a V, slaves with an S, and malefactors with an M.

Answer 2

Hey Motherbrando's,

"To a slaveowner it would be logical to mark his property on two legs just like cattle, or even more since humans are more adroit at escaping.

The Greeks branded slaves with a Delta, Δ, for Δουλος doulos "slave".
Runaway slaves were marked by the Romans with the letter F (for fugitivus).
An intermediate case between formal slavery and criminal law is when a convict is branded and legally reduced, with or without time limit, to a slave-like status, such as on the galleys (in France branded GAL or TF travaux forcés 'forced labour' until 1832), in a penal colony, or auctioned to a private owner. "