Matthias von Gallas, count, a German soldier, born in 1589, died in Vienna in 1647. He belonged to an ancient family of the district of Trent, and acquired military experience under Prince Bauftremont in the war between Spain and Savoy (1616). After the outbreak of the thirty years' war, he distinguished himself in Bohemia and in Tilly's campaign against Christian IV. of Denmark (1626), and became major general. Together with Altringer he captured Mantua in 1629, and they pillaged the city, most of the booty remaining in the possession of Gallas. who was made count and in 1631 field marshal. After having gained the confidence of Wallenstein and cooperated with him against Gustavus Adolphus near Nuremberg and at Lutzen, he was said to have been the first to disclose to the emperor his chief's ambitious designs. It is certain that he was early aware of Wallenstein's impending disgrace, and was among those who refused to attend when he appealed to his officers at Pilsen. On Wallenstein's removal Gallas succeeded him, and was made duke of Friedland. When, after the assassination of Wallenstein (1634), the future emperor Ferdinand III. became his father's generalissimo, Gallas commanded under him, with Piccolomini, in the battle of Nordlingen; and the victory achieved there over Horn and Bernhard of Weimar resulted in the restoration of the S. W. part of Germany to the emperor's dominions.

In 1637 he fought against Baner and Wrangel in Po-merania; but being obliged to retreat next year, he was removed from active service till 1643. He was again commander-in-chief for a short time in 1645, but without retrieving his reputation. His male descendants became extinct in the middle of the 18th century, and Friedland, to which he had added large domains, passed by inheritance to Count Clam, who took the name of Clam-Gallas.