Recent climate research has led Duczko and others to posit that a warming trend around the ninth century led to a population boom in Scandinavia, causing more and more landless young Norsemen to seek their fortunes elsewhere. Not everyone agrees. The National Museum of Ireland’s Wallace says the Vikings may have had a simpler motive: “They had the best iron in the world, trees to cut down and build ships, the best swords and edges on their blades. All the factors were there. They could do it, and they did.”
Whatever the causes for the Vikings’ explorations, evidence of the range of their trading networks began turning up about 150 years ago, when their elaborate burial mounds were first excavated. Well-preserved graves in Birka, Sweden, for example, contained fragments of Chinese silk, and in Norway, the ships in which wealthy Vikings were customarily buried were painted with pigments that may have come from India and the Middle East.
In the 1970s, archaeologists in Dublin found a Viking settlement spread over several acres—and in it more than 3,000 pieces of amber that were probably imported from Denmark. Excavation at Staraya Ladoga, outside St. Petersburg, unearthed a multiethnic settlement that included Viking jewelry, weapons and tools buried amid 1,000-year-old houses. And elsewhere in Russia, archaeologists have uncovered hundreds of Scandinavian graves containing artifacts from the Viking era; in 2006, they found one in the province of Kaliningrad, 500 miles from Norway.
Almost all these sites share a common artifact: thin, silver coins called dirhams. Most of them were made in Baghdad, which was the center of the Arab world from 750 to 950, and they were usually stamped with the year they were minted. Vikings apparently traded furs, amber, ivory and slaves for dirhams, which they then carried with them on their ships. As a result, the coins mark Viking trade routes like shiny silver bread crumbs.
In January 2007, metal-detector hobbyists in Harrogate, England, uncovered a treasure worth millions of dollars that one or more Vikings buried around 927; it included 617 coins, 15 of which were dirhams. Thousands of dirhams dating from 780 to 1050 were found at Viking sites near St. Petersburg. In Poland, archaeologists excavating a Viking settlement near Gdansk found nearly 800 coins dating from 780 to 840, almost all of them Arabic. Other Arabic coins made their way to France, Ireland, Iceland and Greenland. “What we’re seeing is the remnants of an extremely intricate network of barter trade,” says historian Jonathan Shepard of St. Kliment Ohrid University in Sofia, Bulgaria. “It’s a weird combination of coercion and tribute side by side and intermingled with bartering.”
By the 11th century, Vikings began adopting the languages and customs of local peoples, even settling in and intermarrying from Ireland to Russia. Researchers at the universities of Leicester and Nottingham, in England, found that up to half the DNA from men in northwest England matches Scandinavian genetic types.
All that wandering would have been impossible without ships—which is where Erik Nielsen and the rest of the Sea Stallion’s crew come in. For much of the 20th century, archaeologists assumed that Viking ships all resembled a vessel excavated in Norway in 1880. Known as the Gokstad ship, for the farm on which it was found, it dated to the year 900. The ship was “clinker-built,” meaning it was constructed of overlapping planks, which made it stout, flexible and light, with a sail and room for 32 oarsmen. In 1893, Magnus Andersen sailed a replica from Norway to Chicago for the World’s Fair. “Gokstad was thought to be universal, whether trader or raider,” says Niels Lund, a Viking historian at the University of Copenhagen. But a 1962 discovery forced researchers to abandon the idea that the Vikings had only one kind of ship.
At the bottom of a fjord near Roskilde, archaeologists found remnants of five Viking ships piled one atop the other. Dubbed the Skuldelev ships, for a nearby town, each had had a specialized role. One had been a fishing boat; two were cargo ships, so easy to handle that a crew of eight or nine could move 20-ton loads; and one was a warship that could carry about 30 people. The fifth ship, a raider named the Skuldelev, was the largest.
It was 98 feet long but just 12 feet wide. Its keel reached just three feet below the surface, and its masts and sail could be lowered so the ship could approach fortifications and settlements with stealth. It could accommodate 65 armed men. “This is a boat for warriors,” says Soren Nielsen, head boat builder at the Viking Ship Museum in Roskilde.
Because only about 20 percent of the Skuldelev 2 could be recovered, the only way to determine its capabilities for certain was to reconstruct it and put it to sea. In 2000, Nielsen and his colleagues at the ship museum began working with scientists to build an accurate replica. They used thousand-year-old methods and reproductions of tools from that time, which meant carving each of the ship’s 90 oak planks with axes, wedges and hammers. After four years and almost $2.5 million, the eight builders had their replica. They called it Sea Stallion From Glendalough for the Irish village where Vikings used to procure oak for their ships. With its narrow beam and shallow draft, the Sea Stallion could navigate just about any river in Europe. But how would it fare on the open sea?