The Atlantic Bronze Age is marked by economic and cultural exchange that led to the high degree of cultural similarity exhibited by the coastal communities from Central Portugal to Galicia, Armorica and Scotland, including the frequent use of stones as chevaux-de-frise, the establishment of cliff castles, or the domestic architecture sometimes characterized by the round houses. Commercial contacts extended from Sweden and Denmark to the Mediterranean. The period was defined by a number of distinct regional centres of metal production, unified by a regular maritime exchange of some of their products. The major centres were southern England and Ireland, north-western France, and western Iberia. The items related to this culture are frequently found forming hoards, or they are deposited in ritual areas, usually watery contexts: rivers, lakes and bogs. Among the more noted items belonging to this cultural complex we can count the socketed and double ring bronze axes, sometimes buried forming large hoards in Brittany and Galicia; war gear, as lunate spearheads, V-notched shields, and a variety of bronze swords —among them carp's-tongue ones— usually found deposited in lakes, rivers or rocky outcrops; and the elites feasting gear: articulated roasting spits, cauldrons, and flesh hooks, found from central Portugal to Scotland. The origins of the Celts were attributed to this period in 2008 by John T. Koch and supported by Barry Cunliffe, who argued for the past development of Celtic as an Atlantic lingua franca, later spreading into mainland Europe. They argue that communities adopted early Late Bronze AgeUrnfieldelite status markers such as grip-tongue swords and sheet-bronze metalwork, along with new specialist know-how needed for their production and ritual knowledge about their 'proper' treatment upon deposition. which they see as indicating possible processes linked to language shift. In 2013, Koch saw this east to westelite contact as the simplest explanation for the genesis of Celtic languages with a Proto-Celtic homeland in west-central Europe. However, this stands in contrast to what remains the more generally accepted view that Celtic origins lie with the Central EuropeanHallstatt C culture.
