What’s blazon and who does it marshall? Where do these terms come in?
They aren’t parts of heraldic arms. Blazon is the language of heraldry, while marshalling is the art of correctly arranging armorial bearings on the arms
It’s the terminology, the jargon or argot used to describe the whole field of heraldry. This language describes the field, charges, and sub-charges. Using this known language, a coat-of-arms, crest, or badge can easily and accurately be reproduced.
And marshalling is the art of correctly arranging armorial bearings on the arms. To better understand this language, many of the terms used are of French origin, so the adjectives are placed after, not before, the nouns.
A baron, knight, or higher peer of the realm, may display a coronet of rank between the shield and helmet. In Continental heraldry, the coronet is above the crest. Anyone below this rank should not display a coronet.
Two or more coats of arms can be combined on one shield. This tells a longer tale of inheritance, property, or occupation of an office.
Marshalling divisions can take different geometic patterns
Quartering to the Extreme
Called the Grenville Diptych, this was produced between 1822 and 1839. There are 719 quarterings of the family.
The display of arms includes ten variations of the English Royal arms, plus the arms of Spencer, De Clare, Valence, Mowbray, Mortimer, and De Grey, and others.
Grenville Diptych image courtest Wikipedia
Due to marshalling of the arms, stained glass and brasses on the floors of churches can be of great help to determine family connections,