In ancient times, the fort probably had the tactical task of monitoring the valley of Mureș and the strategic function of controlling an area in which numerous Dacian fortresses had been located before the Roman occupation.

The Roman health resort Germisara, today Geoagiu-Băi, developed five kilometres north of the fort and made use of the thermal springs of the mountains.

The name Germisara is of Dacian origin, means "hot water" (germi = heat, sara = waterfall) and refers to the local thermal springs.

Vexillationes of Legio XIII Gemina and Numerus Peditum Singularium Britannicianorum, both of which are documented by numerous brick stamps and inscriptions, are mentioned as the ancestral units of the fort Cigmău.

Legio XIII Gemina had already taken part in the first Dacian war of Trajan and then moved into its headquarters in the legionary camp Apulum (modern Alba Iulia), from where it detached to various other locations.

The Numerus Peditum Singularium Britannicianorum, which was first stationed in the province Moesia Superior, is documented from the year 110 in Dacia, where it probably remained until the end of the Roman occupation of the country.

This only changed with the evaluation of aerial and satellite photographs by William S. Hanson and Ioana A. Oltean and the following archaeological excavations under the direction of Adriana and Eugen Pescaru in the years 2000 to 2002.