Kentish manufacture before 600 included glass beakers and jewelry. Kentish jewellers were highly skilled, and before the end of the sixth century they gained access to gold. Goods from Kent are found in cemeteries across the channel and as far away as at the mouth of the Loire. It is not known what Kent traded for all of this wealth, although it seems likely that there was a flourishing slave trade. It may well be that this wealth was the foundation of Æthelberht's strength, although his overlordship and the associated right to demand tribute would have brought wealth in its turn.