All 8 Uses of

principal
in
The Iliad by Homer - (translated by: Pope)

Nor is this judicious and astonishing diversity to be found only in the principal quality which constitutes the main of each character, but even in the under parts of it, to which he takes care to give a tincture of that principal one.†
Book Pref.

principal = most important; or person that is most important

Nor is this judicious and astonishing diversity to be found only in the principal quality which constitutes the main of each character, but even in the under parts of it, to which he takes care to give a tincture of that principal one.†
Book Pref.

Longinus has given his opinion, that it was in this part Homer principally excelled.†
Book Pref. *

principally = primarily or most importantly

We see the motion of Hector's plumes in the epithet Korythaiolos, the landscape of Mount Neritus in that of Einosiphyllos, and so of others, which particular images could not have been insisted upon so long as to express them in a description (though but of a single line) without diverting the reader too much from the principal action or figure.†
Book Pref.

principal = most important; or person that is most important

Thus on whatever side we contemplate Homer, what principally strikes us is his invention.†
Book Pref.

principally = primarily or most importantly

We ought to have a certain knowledge of the principal character and distinguishing excellence of each: it is in that we are to consider him, and in proportion to his degree in that we are to admire him.†
Book Pref.

principal = most important; or person that is most important

His similes are like pictures, where the principal figure has not only its proportion given agreeable to the original, but is also set off with occasional ornaments and prospects.†
Book Pref.

It is not to be doubted, that the fire of the poem is what a translator should principally regard, as it is most likely to expire in his managing: however, it is his safest way to be content with preserving this to his utmost in the whole, without endeavouring to be more than he finds his author is, in any particular place.†
Book Pref.

principally = primarily or most importantly

Definitions:

(1) (principal)
most important; or person who is most important
The exact meaning of principal can depend upon its context. For example:
- "the principal idea" or "the principal performer" -- the most important
- "the principal of the school" -- the person in charge
- "a principal of a company" -- an owner or person with controlling authority
- "the principal in a transaction" (as contrasted to the agent) -- the person on whose behalf an agent acts
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

See a comprehensive dictionary for specialized senses in finance, architecture, law, chemistry, and music.