Read this and answer the question. If the question is unanswerable, say "unanswerable".

The Romans under Nero Claudius Drusus established a military outpost belonging to the Germania Superior Roman province at Strasbourg's current location, and named it Argentoratum. (Hence the town is commonly called Argentina in medieval Latin.) The name "Argentoratum" was first mentioned in 12 BC and the city celebrated its 2,000th birthday in 1988. "Argentorate" as the toponym of the Gaulish settlement preceded it before being Latinized, but it is not known by how long. The Roman camp was destroyed by fire and rebuilt six times between the first and the fifth centuries AD: in 70, 97, 235, 355, in the last quarter of the fourth century, and in the early years of the fifth century. It was under Trajan and after the fire of 97 that Argentoratum received its most extended and fortified shape. From the year 90 on, the Legio VIII Augusta was permanently stationed in the Roman camp of Argentoratum. It then included a cavalry section and covered an area of approximately 20 hectares. Other Roman legions temporarily stationed in Argentoratum were the Legio XIV Gemina and the Legio XXI Rapax, the latter during the reign of Nero.

For how many years was Argentorate made the toponym of the Gaulish settlement?
unanswerable