The Pandya seems to be the most prominent of the three "ventar" rulers. There are even references to a Pandya queen from 3rd century BCE representing a confederacy of the Tamil countries. Madurai, in south Tamil Nadu, was the most important cultural centre in south India as the core of the Tamil speakers. Megalithic relics such as menhirs, dolmens, urn burials, stone circles and rock-cut chambers/passages can be found in south India. Burial goods include iron objects, ivory ornaments, Black-and-Red Ware and even some Roman Imperial coins. The so-called "velir" hill chieftains are assumed to be associated with these megalithic burials.