It was part of the Roman frontier system of the Limes Transalutanus in a strategic position to the north of the Rucăr–Bran Pass.

[3] The second construction phase was a stone fort of 118 × 124 m with the porta praetoria on the NE side and walls 1.5-1.7 m thick.

Approximately 78 m NNE of the stone fort a building consisting of two rooms with a semicircular apse oriented to the NW was found.

The IV Vindelicorum, a peditata quingenaria cohort, was moved from Arzbach to Râșnov sometime in the beginning of the 3rd century and built a similar fort to that at Arzbach judging by the unusual character of the ancillary buildings inside.

[9] Notably the headquarters building has a length-to-width ratio is reversed in relation to that of the fort, and there is a narrow courtyard, similar to the one at Râșnov.