David Ungnad von Sonnegg was the Holy Roman Ambassador to the Ottoman Empire from 1572 to 1578.
[1] Sonnegg served Frederick II of Denmark during the Northern Seven Years' War from 1563 to 1570.
He travelled to Constantinople in 1572 as envoy of Holy Roman Emperor Maximillian II, carrying a tribute to the Sultan.
Sonnegg was accompanied by a retinue of 20, including the Flemish courtier and diarist Lambert Wyts, who wrote a book on his experiences in Turkey.
Ungnad was involved in an counterintelligence mission involving "reporting on, and attempting to prevent, an Ottoman spy mission" operated by a recent convert to Islam named Markus Penckner.