Prince Eustachy Erazm Sanguszko (1768–1844) - Polish nobleman, general, military commander, diplomat and politician.
He was a deputy in the Great Sejm, the parliament that deliberated 1788–1792 and produced the 3 May Constitution. Sanguszko then participated in the Polish-Russian War of 1792 as a national cavalry brigadier, where he fought at the Battle of Zieleńce. During the Kościuszko Uprising in 1794 he was a major general and a division commander. At the Battle of Szczekociny he saved Kościuszko's life, then fought and was wounded during the siege of Warsaw. He was a member of the general staff of Napoleon Bonaparte during the Russian campaign (with the rank of brigadier general) and took part in the march on Moscow. In the Duchy of Warsaw he was the vice-Regimentarz of the pospolite ruszenie. To protect family land holdings in the Ukraine Sanguszko refused to participate in Prince Poniatowski's 1813 campaign, for which the commander in chief, an old friend, punished him harshly with a dishonorable discharge from the army. After the fall of Napoleon, Sanguszko settled on his ancestral lands that included the battlefield of Zieleńce. There he often pondered on the past historic events in which he took part and described his thoughts in the "Memoirs". Between 1817–1820 he was the governor marshal of Volhynia. He was decorated with the Polish Knight's Cross of the Virtuti Militari and Chevalier of the French Legion of Honour.
He married Klementyna Czartoryska on June 26, 1798 in Sławuta and had with her three children: Dorota (1799-1831), Roman (1800-81), and Władysław (1803-70). Prior to this, he had been romantically involved with Julia Lubomirska.