The basic meaning of this term is a naval militia. It is a term taken from the beginning of the Anglo-Saxon period in England all they way back around 790-800.

The system was used to raise both armies and navies during time of need. This prevented the king from needing to spend large amounts of money to spend on military matters. The system had been in place all over Europe during the medieval period. In fact it is claimed the Viking system of naval allocations was based on a Germanic system from 98AD.

The word origin is some what strange, leiðangr (Old Norse), leidang (Norwegian), leding, (Danish), ledung (Swedish), expeditio (Latin) or sometimes lething (in English language).

The system was straight forward and simple. Area A must allocate 1 ship and crew. Area B must allocate 2 ships and crews. Area C must allocate 3 ships and crews. The amount to be allocated was calculated by population and natural resources in a certain area. Some locations would only be requested to send materials to make a ship where as others would have to send men, material, and build the ships.

The system was used by Alfred the Great to become the father of the English navy. Oddly enough a similar system is still in use today.