It lasted until it was overwhelmed by the Gaulish Celts in the 4th century BC and was finally incorporated into the hegemony of the Roman Republic. Golasecca culture is divided for convenient reference into three parts: the first two cover the period of the 9th to the first half of the 5th century BC; the third, coinciding with La Tène A-B of the later Iron Age in this region and extending to the end of the 4th century BC, is marked by increasing Celtic influences, culminating in Celtic hegemony after the conquests of 388 BC. The very earliest finds are of the Late Bronze Age (9th century BC), apparently building upon a local culture. In Golasecca culture some of the first evolved characteristics of historic society may be seen in the specialized use of materials and the adaptation of the local terrain. The early-period habitations were circular wooden constructions along the edge of the river's floodplain; each was built on a low basement of stone round a central hearth and floored with river pebbles set in clay. Hand-shaped ceramics, made without a potter's wheel, were decorated in gesso. The use of the wheel is known from the carts in the "Tomb of the Warrior" at the Sesto Calende site. Amber beads from the Baltic Sea, doubtless brought down the Amber Road, and obsidian reveal networks of long-distance trade. From the 7th century onwards some tombs contain burial goods imported from Etruscan areas and Greek objects. The settlements depended on domesticated animals: remains reveal the presence of goats, sheep, pigs, cattle and horses. Some legume and cereal crops were cultivated; nuts and fruits were collected. The dugout boats from Castelletto Ticino and Porto Tolle are conserved at the museum of Isola Bella. Metal, though rare, was in increasing use. The old sites—Golasecca, Sesto Calende, Castelletto Ticino—maintained their traditional autochthonous character through the 6th century BC, when outside influences begin to be detectable. At the beginning of the 5th century BC, pastoral practices resulted in the development of new settlements in the plains. Deciphered written characters (the "Lepontic alphabet") are found incised in ceramics or on stone, in the Celtic "Lepontic language". The Golasecca culture is best known by its burial customs, where an apparent ancestor cult imposed respect of the necropolis, a sacred area untouched by agrarian use or deforestation.