Lake Mälaren was the trade, power and commerce center of ancient Svealand. The island settlement of Helgö in Lake Mälaren was the heart of the Svears manufacture center. The Svears had a commerce and trade alliance with the Gotar of the island of Gotland in the Baltic. Svealand iron production was being exported to Latvia and Lithuania by merchants from Gotland who were regular visitors to Helgö and later Birka and Sigtuna in Lake Mälaren. Archaeological excavations revealed a large and centralized metalworking industry at Helgö between the 5th and 6th centuries AD.

The ruins of ancient Helgö were barely noticeable until excavations of the settlement were carried out for first time in the 1950's and 60's. Evidence of the importance of trade to the Svear can be seen in the amount of foreign goods found in the archaeological investigations and in accounts and legal documents recorded by those merchants that had contact with the Svear.

Items found at Helgö which give evidence to the extent of Svealand trade were a small Buddha statue from north India and a christening spoon from Egypt, both dating from 6th century. In addition, twenty six tiny pictures in delicate metalwork were also discovered at Helgö at what is believed to be a sacred site. Scenes depicted on them are usually of a man and woman facing one another, sometimes embracing and sometimes separated by a leafy branch, and the generally accepted explanation is that they represent the Vanir fertility deities, who could bring blessing to the land, to flocks and herds and to human families.

The manufacture of jewellery and metalworking at Helgö and valuable grave goods found with those buried at Vendel and similar cemeteries in the area probably owed their wealth partly to their control of the routes from Lake Mälaren where iron and metal was worked in such places as Helgö.