Tumuli, whose tradition dates back to the Bronze Age at the latest, are among the most widespread monumental tombs. The tradition of subterranean burial seems to have been deeply rooted in Anatolia, despite the fact that with the arrival of foreign ethnicities, the variety of tombs and burial customs had expanded. As the sixth century B.C. advanced, tumulus burials seemingly became the most popular form of monumental funerary architecture. In western Anatolia – where the local architecture had been the inspiration for the construction of various sepulchral monuments whose owners belonged to the ruling royal, aristocratic or civic elite – transformation of elite burials may be understood in the wake of political settlement. Traditional Lydian burial customs were part of this process as well. Lydian type of burial mounds can be seen to have extended into the Ionian, Carian and Lycian border areas, while an enhancement of the local tumuli type is attested in Ionia, Caria and Lycia.