Minium (red lead) was the primary orange-red used in medieval manuscript illumination — the source of the word "miniature" (from minium, not from "small"). Its brilliant, opaque orange-red was unrivalled until cadmium.

Minium is historically the colour of beginnings — manuscript rubrics (from Latin rubrica, red ochre) used red-orange to mark chapter beginnings and important passages. It is the colour that draws the eye to what matters.

The word "miniature" comes from minium — medieval illuminators used it to paint the small detailed images in manuscripts. The connection to smallness came only later, from the small size of manuscript illustrations. Many Books of Hours show darkened passages where minium has degraded.