The name is Thracian and means "spring city", referring to the hot springs there. The earliest preserved mention of the city is in a list of 135 Roman Municipia in Thrace from 106 C.E.
The city's name originates from its association with natural hot springs, derived from the Thracian language and signifying "spring city." This connection is first mentioned in a historical record listing 135 Roman Municipalities in Thrace dating back to 106 C.E.