The
leiðangr was a system organizing a coastal fleet with the aim of defence, coerced trade, plunderings, and aggressive wars. The leidangs were centered upon a ship. The organizational unit was the ship itself with the men providing their own equipment and provisions for the journey. The ship's company agreed to serve for a certain period of time, normally, the fleet levy was on expeditions for two or three summer months. It was composed of free men who owned farms. The
leiðangr differed from conventional
feudalism in that the expeditions gathered around leaders based on military merit, rather than noble status. The farmers of each district had to build and equip a rowed sailing ship. The size of the ships was defined as a standardized number of oars, initially 40 oars, later 24 oars. In Norway, there were 279 such districts in 1277, in Denmark two-three times as many. The head of a district was called
styrimaðr or
styræsmand, steersman, and he functioned as captain of the ship. The smallest unit was the crew of peasants who had to arm and provide for one oarsman (
hafnæ in Danish,
hamna in Swedish,
manngerð in Old Norse). In Sweden a
hamna was made up of two
attung, which was "two eighth parts of a village". One attung seems to have been equal to the land area it took to feed an ordinary family (around 12 acres, see
Hide (unit),
Virgate and
Oxgang for English equivalents). Each attung also regard as having a "share" in the raid, so one who owned two attung had twice as much chance to go on the raid as one who owned only one. Those who owned less than an attung had to team up with others to form a unit of one attung and share the burdens as well as the profit. According to the
Law of Uppland, the
hundreds of
Uppland, all in all 22 hundreds (Tiundaland; providing 10 hundreds, Attundaland; providing 8 hundreds and Fjärdhundaland; providing 4 hundreds) each of which providing four ships (four ships, each with 24 crewmen and a steersman, each equals 100 men). Also, those of
Västmanland two ships and those of
Roslagen one ship (the name indicate that this was seen as just one ship's crew but they were not part of a hundred and might have had the same rights/function of whole hundred only fewer people). The older laws regulating the
leiðangr (the Norwegian "Older Law of the Gulating" dates to the 11th or 12th century) require every man to, as a minimum, arm himself with an axe or a sword in addition to spear and shield, and for every rowbench (typically of two men) to have a bow and 24 arrows. Later 12th-13th century changes to this law code list more extensive equipment for the more affluent freemen, with helmet, mail hauberk, shield, spear and sword being what the well-to-do farmer or burgher must bring to war. In 12th-13th-century sources detailing the 11th century,
jarls are mentioned as the chieftain of the
leiðangr. In the 12th century, a bishop could also be head of the fleet levy, although typically nobles led levies in the 12th to 14th centuries. == During the Baltic Crusades ==