1648 - Formal Recognition of Independent Switzerland
The northern Swiss Plateau was settled by the Alemanni when they moved into the void left by a crumbling Western Roman Empire in 406A.D. By the end of the 1st millennium, the Alemanni had become part of the Frankish empire, under which the Duchy of Alamannia, later becoming the Duchy of Swabia, extended its influence across a large part of what was to become Switzerland - the cities of Freiburg in Germany and Bern in Switzerland both owe their foundation to the Swabian Zähringen family.
It was the Swabian Holy Roman Emperors - the Hohenstaufens - who first granted large parts of what was to become Switzerland 'Imperial Immediacy'. This placed them under direct control of the Holy Roman Emperor, free from the authority of any local lord. Following the collapse of the Swabian Dynasty in the 13th century the ascendant House of Habsburg, with its origins in Swabia but now rulers of the Archduchy of Austria, made several attempts to bring the Swiss cantons under their personal control.
In defending their independence the Swiss soon gained a reputation for martial prowess (to the extent that Pope Julius II recruited them as the Papal guard in 1506, a service the Swiss Guard performs to this day). Following victory over an Habsburg army in the Swabian War of 1499, the Old Swiss Confederacy won a de facto independence within the Holy Roman Empire, and quickly grew to 13 members. In the Peace of Westphalia of 1648 which ends the Thirty Years' War, Switzerland is formally recognised as an independent nation.
Today, spoken Swiss German - an Alemannic dialect - is one of the four languages spoken in Switzerland, and the most used (64% of Swiss are Swiss German speaking). Compared to other former Alemannic regions, Switzerland is the only area where an Alemannic dialect is a primary language rather than an endangered, restricted, or otherwise subsidiary dialect.
Image Credit: Map showing the growth of the Old Swiss Confederacy during the 13th to 16th centuries - http://commons.wikimedia.org/wiki/File:Old_Swiss_Confederation.jpg