The term blazon is sometimes used to describe medieval Mamluk emblems, but these were used to identify official positions at the Mamluk court, rather than having the specific function of identifying a particular person or family.
The first illustration of a medieval blazon can be found on the Bayeux tapestry from the eleventh century. See here.
Source: Shorter Oxford English Dictionary: 'Blazon'
Wikipedia (retrieved 21 April 2017).
Digital source of illustration ((retrieved 21 April 2017).)
GVE