Columbia subject headings:
Thirty Years' War, 1618-1648.
Werth, Johann, 1591-1652.
Harvard subject headings:
Thirty Years' War, 1618-1648.
Werth, Johann, Graf von, -1652.
Princeton subject headings:
Generals--Germany--Biography.
Thirty Years' War, 1618-1648.
Werth, Johan, 1590 or 91-1652.