First off, to answer Bruce's question--"great" is used in the European context as "big". Thus, a "great sword" is a "big sword".

Swords that were made for two-handed use were first seen employed by the Germans--specifically, by German mercenaries of Manfred of Sicily, during the Battle of Benevento against the French in 1266. Such swords were termed by the French as Grans espees d'Allemagne--"Great swords of Germany". According to Ewart Oakeshott, there are many references to such weapons in the 13th and 14th centuries--"Grant espees", "Grete Swerdes", etc.

By later (Renaissance) standards, these early great swords were actually "ba$tard swords"--i.e., they had a grip long enough for both hands, but were light enough to use with one hand as well. "True" two-handers, on the other hand, could only really be wielded effectively with both hands. Because of its unique characteristics, the ba$tard sword was thus not a "legitimate" two-hander or one-hander (hence the name).

The Highland Scots developed their own style of great sword, that was actually of true two-hander proportions. This weapon is commonly called a "claymore", though this specific term was actually first used to describe the later, single-handed, basket-hilted broadsword. In any case, the term "claymore" can be found in historical sources referring to both weapons. It is an English corruption of the Gaelic claidheamh mor, which means--you guessed it--"great sword".

In the 15th and 16th centuries, the "true" two-handed sword was really developed to its height. To the Germans, this weapon was commonly known as a zweihander ("two-hander"), bidenhander ("both-hander"), or a schlachtschwert ("battle sword"). It was one of the favored weapons of the doppelsoldner ("hirelings who draw double-pay"), who were the elite troops of the German landsknechte ("servants of the land") mercenaries.

This fully developed German two-hander was the biggest type of European sword--being up to 66 inches in length, and weighing in the 4.5-8 lb range. It featured a long ricasso (the blunt base of the blade), which was typically covered in leather, and could be grasped when one wanted to shorten one's grip on the weapon for various actions. When holding the sword this way, the parrierhaken ("parrying hooks") served as a secondary handguard. There were also often two side rings, one on each side of the quillon block.

Here's a German landsknecht two-hander:

http://therionarms.com/reenact/com348.jpg

Two-handers of this type (and some of simpler form--without the side rings or parrying hooks or both) were used in other parts of Europe as well. The Italians termed this weapon a spada da due mani ("two-handed sword") or spadone ("great sword"). In Spain, it was called an espadon ("great sword"), though a smaller, ba$tard-sword-sized version (like a German zweihander in minature) was preferred, and this was called a montante. To the French, the two-hander was known simply as an espee a deux mains. The English referred to it as a "two-handed sword", or a "slaughter sword" or "slath sword" (the latter two terms being corruptions of the German schlactschwert).

In military service, the two-hander was used by assault troops, to give close support to pikemen when two pike-blocks crashed together (halberdiers were also used in this role). They were also sometimes employed by members of the verloren haufe ("forlorn hope")--the advance "suicide squad" that attempted to break the cohesion of the enemy pike unit before the main force came up. Two-handers were also valued for the defense of fortress gateways, breaches in walls, etc. The Knights of Saint John made use of this weapon during their defense of Rhodes in 1522 and Malta in 1565. The use of the two-hander by the Knights was respected and feared by the Ottoman Turks. The final military role of the two-hander was in the defense of the standards (flags) of the army.

Although casually referred to purely as a military weapon, the two-hander was also taught in civilian fencing schools of the time, and was used by city guards on their patrols--it was favored for this because, as fencing master Giacomo di Grassi noted, a man with a two-hander could contend with several opponents armed with single-handed weapons.

I would be curious to know if any of the above roles correspond to the Japanese use of the no-dachi--perhaps Charles knows?

If you have any other questions, I'll do my best to answer them.

Peace,

A_M_P