Pl.: tegulae mammatae

Literally meaning ‘nipple tiles’, these square or rectangular terracotta tiles had projecting bosses in the corners of one side, so that a cavity was created when placing these tiles vertically against a wall. The tiles were fixed to the wall with iron T-shaped clamps. The open space between wall and tiles connected with the hypocaust, enabling the hot gases to rise ‘inside’ the wall. This system of wall heating is mainly found in Republican and early Imperial baths, and was gradually replaced by tubuli.

Tegulae mammatae in situ in the Stabian baths of Pompeii (R) and close up of their use in the Forum Baths of the same city (photos Konogan Beaufay).