The Old Swiss Confederacy (Modern German: Alte Eidgenossenschaft; historically Eidgenossenschaft, after the Reformation also République des Suisses, Republica Helvetiorum "Republic of the Swiss") is the precursor of modern-day Switzerland.It is a loose confederation of largely independent small states called cantons that form during the 14th century.

From a nucleus in what is now Central Switzerland, the confederacy expands to include the cities of Zürich and Berne by the mid 14th-century, forming a rare union of rural and urban communes, all of which have the status of imperial immediacy within the Holy Roman Empire.This confederation of eight cantons (Acht Orte) persists for more than a century, enjoying great political and military successes, culminating in the Burgundy Wars in the 1470s, which establish it as a power holding its own in the complicated political landscape dominated by France and the Habsburgs.

These successes result in the accession of more confederates, increasing the number of cantons to thirteen by 1513 (Dreizehn Orte).

The confederacy pledges neutrality in 1515, and again in 1647, under the threat of the Thirty Years' War, even though many Swiss serve privately as mercenaries in the Italian Wars and throughout the Early Modern period.After the Swabian War of 1499, the confederacy is a de-facto independent state throughout the early modern period, although still nominally part of the Holy Roman Empire until 1648.

However, the Swiss Reformation divides the confederates in a Reformed and a Catholic party, resulting in numerous internal conflicts during the 16th to 18th centuries, and as a result the federal diet or Tagsatzung is often paralyzed by hostilities between the two factions.The Swiss Confederacy finally falls to the invasion by the French Revolutionary Army in 1798, after which it is transformed it into the short-lived Helvetic Republic.