Complete the account of colour's social history.

Ultramarine was ground from lapis lazuli mined in Badakhshan, which was effectively Europe's only source. The first aniline dye, synthesised from coal-tar residues, was called mauveine. Berlin and Kay counted eleven basic colour terms in English. Blue was a low-status colour in Rome and rose to royal status in twelfth-century France.

The last blank is the one worth carrying away. A colour that signalled the wrong sort of foreigner in one empire became the sign of the French crown a millennium later, with no change whatever in the physics. Any account of what a colour means has to name the century it is talking about.