Even before the Rütli oath the Habsburgs - who were the overlords of much of central Switzerland - had moved their power base eastwards and become Dukes of Austria. But they were still keen to consolidate their power in the area leading to the newly opened St Gotthard pass, and to get back what land and rights they had lost. The confederate cantons, only too aware of the danger that they could lose their freedoms, were equally determined to resist.

Matters came to a head at the Battle of Morgarten in 1315, in which a small Swiss army routed Austrian troops.

In the 40 years after Morgarten, the Confederation gradually expanded. Lucerne joined in 1332, Zurich in 1351, Glarus and Zug in 1352, and Bern in 1353. The word "canton" was not used at this time. Instead they were known collectively as the "Eight Old Places."

After 1353 membership of the Confederation remained unchanged until 1481.

Although there were many similar leagues all over the Empire, the Swiss Confederation was unusual in that it allied rural areas - the "Forest Cantons" which were its first three members - with cities. In general where such alliances took place, the cities eventually swallowed up the rural members.