With the support of the nobles, Wenceslas took control of the government.
To prevent disputes between him and his younger brother Boleslav, they divided the country between them, assigning to the latter a considerable territory.

After the fall of Great Moravia, the rulers of the Bohemian Duchy had to deal both with continuous raids by the Magyars and the forces of the Saxon and East Frankish king Henry the Fowler, who had started several eastern campaigns into the adjacent lands of the Polabian Slavs, homeland of Wenceslas's mother.
To withstand Saxon overlordship, Wenceslas's father Vratislaus had forged an alliance with the Bavarian duke Arnulf, a fierce opponent of King Henry at that time.
The alliance became worthless, however, when Arnulf and Henry reconciled at Regensburg in 921.

Early in 929, the joint forces of Duke Arnulf of Bavaria and King Henry I the Fowler reached Prague in a sudden attack that forced Wenceslas to resume the payment of a tribute first imposed by the East Frankish king Arnulf of Carinthia in 895.

He introduced German priests, and favoured the Latin rite instead of the old Slavic, which had gone into disuse in many places for want of priests.
He also founded a rotunda consecrated to St. Vitus at Prague Castle in Prague, which exists as present-day St. Vitus Cathedral.

Henry had been forced to pay a huge tribute to the Magyars in 926 and needed the Bohemian tribute, which Wenceslas probably refused to pay after the reconciliation between Arnulf and Henry.
Another possible reason for the attack was the formation of the anti-Saxon alliance between Bohemia, the Polabian Slavs, and the Magyars.
With the support of the nobles, Wenceslas took control of the government. To prevent disputes between him and his younger brother Boleslav, they divided the country between them, assigning to the latter a considerable territory.
After the fall of Great Moravia, the rulers of the Bohemian Duchy had to deal both with continuous raids by the Magyars and the forces of the Saxon and East Frankish king Henry the Fowler, who had started several eastern campaigns into the adjacent lands of the Polabian Slavs, homeland of Wenceslas's mother. To withstand Saxon overlordship, Wenceslas's father Vratislaus had forged an alliance with the Bavarian duke Arnulf, a fierce opponent of King Henry at that time. The alliance became worthless, however, when Arnulf and Henry reconciled at Regensburg in 921.
Early in 929, the joint forces of Duke Arnulf of Bavaria and King Henry I the Fowler reached Prague in a sudden attack that forced Wenceslas to resume the payment of a tribute first imposed by the East Frankish king Arnulf of Carinthia in 895.
He introduced German priests, and favoured the Latin rite instead of the old Slavic, which had gone into disuse in many places for want of priests. He also founded a rotunda consecrated to St. Vitus at Prague Castle in Prague, which exists as present-day St. Vitus Cathedral.
Henry had been forced to pay a huge tribute to the Magyars in 926 and needed the Bohemian tribute, which Wenceslas probably refused to pay after the reconciliation between Arnulf and Henry. Another possible reason for the attack was the formation of the anti-Saxon alliance between Bohemia, the Polabian Slavs, and the Magyars.
Wenceslaus I, Duke of Bohemia