The Roman Empire had conquered Raetia in 15 BCE.

Under emperor Diocletian (late third century CE), the existing settlement of Curia Raetorum had been made the capital of the newly established province of Raetia prima.

Chur In the fourth century had become the seat of the first Christian bishopric north of the Alps.

Despite a legend assigning its foundation to an alleged Briton king, St. Lucius, the first known bishop is one Asinio in 451.

After the invasion of the Ostrogoths, it had been rechristened Theodoricopolis; in the sixth century it had been conquered by the Franks.

The city has suffered several invasions, including one by the Magyars in 925-926, when the cathedral is destroyed.

Open war between the Swiss Confederacy and the Swabian League breaks out over a territorial conflict in the Grisons, where during the fifteenth century a federation similar to the Eidgenossenschaft had developed.

Like the Swiss, the Three Leagues have achieved a far-reaching autonomy, but also are involved in constant struggles with the Habsburgs, who rule the neighboring territories to the east and who keep trying to bring the Grisons under their influence.

During the 1470s and 1480s, duke Sigismund had succeeded in acquiring, step by step, the high justice over most of the communes of the Zehngerichtebund ("League of the Ten Jurisdictions" in the Prättigau, the youngest of the Three Leagues that had sprung up in the Grisons, having been founded only in 1436), and Maximilian has continued this expansionist strategy.

The Habsburg pressure prompts the Three Leagues to sign a close military alliance with the Swiss Confederacy in 1497-98.

At the same time, the Habsburgs had been involved in a major power struggle with the French kings of the House of Valois over the control of the remains of the realm of Charles the Bold, whose daughter and heiress Mary Maximilian had married.

Maximilian's second marriage in 1493 with Bianca Maria Sforza from Milan had then gotten got the Habsburgs directly involved in the Italian Wars, clashing again with the French kings over the control of the Duchy of Milan.

Emperor Ferdinand II's forces invade the Grisons and Valtelline under Field Marshal Ramboldo, Count of Collalto, head of the Imperial War Council in Vienna.

Ramboldo, charged of conspiring with Venice, travels to Vienna to defend himself but dies on the way in Chur on November 19, 1630.