A prayer before writing or studying from St. Thomas Aquinas (1225 – 1274):

*****

Ineffable Creator,
Who, from the treasures of Your wisdom,
have established three hierarchies of angels,
have arrayed them in marvelous order
above the fiery heavens
and have marshaled the regions
of the universe with such artful skill,

You are proclaimed
the true font of light and wisdom,
and the primal origin
raised high above all things.

Pour forth a ray of Your brightness
into the darkened places of my mind;
disperse from my soul
the twofold darkness
into which I was born:
sin and ignorance.

(Source)