in 1634, led by Butler When his family estates in
Roscrea,
County Tipperary were confiscated in 1616, Walter became a soldier of fortune. He emigrated to
Germany early in the 17th century with his brother, James. Walter and James entered the armed forces of the
Habsburg emperor
Ferdinand II and Walter served with distinction as a colonel in the
Thirty Years' War. In 1631 he and his Irish officers fought under General
Tilly against
MacKay's Swedish regiment laying siege to
Frankfurt-an-der-Oder. Injured and captured by the Swedish, he was accused of being responsible for the loss of the Oder fortress. Butler made King
Gustavus Adolphus of Sweden certify his bravery and after his release appeared at the Imperial headquarters before Field Marshal
Rudolf von Tiefenbach, where his opponents had to withdraw their accusations. In 1632 he joined the armed forces under Wallenstein, who, in view of the Swedish progress, had been again appointed Imperial commander-in-chief by Emperor Ferdinand II. Butler quickly gained the trust of the
Generalissimo and was appointed Colonel of a
dragoon regiment. While the Imperial army fought against the Swedish at
Zirndorf and
Lützen, Wallenstein's envoys were in secret discussions with the opponents, which led to accusations of making peace with the King of Sweden without the consent of the
Emperor. When Wallenstein's treachery was discovered in 1632, it was Butler who "saved the Empire" and arranged his assassination in 1634. He together with the officers John Gordon and
Walter Leslie had the plot executed on 25 February, after the murder of Wallenstein's confidants Christian von Ilow, Adam Erdmann Trčka von Lípa and
Vilém Kinský. According Walter Butler's entry in the
Compendium of Irish Biography (1878): ==Ballinakill Castle==