Subdinum
The site was occupied from the 1st c. B.C. on, but we know little about it in the Late Empire. Ancient harbor installations, however, discovered in the 19th c., indicate that the city was an important economic center as early as the end of the 1st c. B.C.
Towards the end of the 3d c. A.D. Subdinum acquired a fortified circuit wall, still visible today. The outer facing of the walls and of the projecting round towers has a core of mortared rubble faced with small blocks, and is decorated with a simple design of white stones (chevrons, lozenges, bars, small rosettes). Near the Tour Madeleine a very fine ashlar masonry of large blocks may be seen at the base of the walls; it is decorated with arcs, circles, and ovolos engraved in intaglio. One of the city's postern-gates, discovered in 1953 (the rampart has two other gates of the same type), consists of two parallel walls of cyclopean stones supporting a brick vault. The floor of the postern is made up of large flat slabs, on which the side walls rest. This was probably a sea-gate leading directly to the Sarthe, which in this area reached the level of the rampart.
BIBLIOGRAPHYP. Cordonnier-Dietrie, “Informations,” Gallia 12, 1 (1954) 172-75; 15, 1 (1957) 202-3.
M. PETIT