The building of Eumachia was the guildhall of the cloth trade. It was set up by the priestess Eumachia for the 'fullones' or dyers and launderers. This industry was regarded as so important that it could have its guildhall in the forum which was the centre of business life in Pompeii.

The building itself was entered via the forum. Inside there was an open courtyard where cloth would be sold. It also contained a statue of Eumachia. Around this courtyard there was a colonnade. At the back of the courtyard was space for the storage of cloth.