Kossakowski () was a Polish-Lithuanian noble family originated from Mazovia.
They were first mentioned in the 13th century and initially settled in Ciechanów County, from where they branched out to the Grand Duchy of Lithuania, Podolia, Volhynia, and Livonia.
According to family legend, the Kossakowski family traced their origins back to a Roman soldier named Valerius, who, during one of his battles, had a raven land on his helmet and assist him in combat. Hence his nickname, Corvus (the raven). His descendants were said to have arrived in Poland via Hungary. Stanisà Âaw Kazimierz Kossakowski (1837âÂÂ1905), the family historian, identified Gopta Primus Gothorum Heros, who lived around the year 440, as the progenitor of the family. Valerius, according to him, was believed to be his descendant.
The Kossakowski family was first recorded in the 13th century in the Ciechanów Land. In 1224, Konrad I of Masovia granted land to one of his army commanders, WawrzÃÂta/Wawrzyniec Korwin. In the 14th and 15th centuries, the Kossakowski family appeared in the à Âomà ¼a Land, where they established several noble villages named Kossaki. The family gained particular prominence through the sons of Mroczek of Kossaki, Mikoà Âaj Jakub and Stanisà Âaw Wojciech, who held official positions in the Wizna Land. They became the progenitors of the two most significant branches of the family.
The great-grandsons of Mikoà Âaj Jakub Kossakowski, Franciszek Nikodem and Mikoà Âaj, were the first members of the family to attain the office of starosta, successively becoming starostas of à Âomà ¼a. distinguished himself in the Battle of Kircholm, and his son settled in the Grand Duchy of Lithuania, eventually becoming the castellan of Mà Âcisà Âaw. From him descends the Lithuanian magnate branch of the Kossakowski family.
The heir to the Lithuanian estates of the family was Jan Eustachy's grandson, Dominik Kossakowski, the founder of the town of Jonava. He had four sons: Michaà Â, who became the voivode of Vitebsk and Brasà Âaw; Szymon Marcin, the Grand Hetman of Lithuania; Józef Kazimierz, the bishop of Livonia; and Antoni, castellan of Livonia. Szymon Marcin and Józef Kazimierz were sentenced to death and executed for treason against the fatherland. Antoni established a branch of the family in , and Michaà  in . At the end of the 18th century, Michaà  Kossakowski received for the family the title of count, granted by the imperial court in Vienna. The line in Vaitkuà ¡kÃÂs maintained a high aristocratic status within the Russian Empire. Successive heirs, Józef Kossakowski and Stanisà Âaw SzczÃÂsny Kossakowski, each left only one son, which helped preserve the estate from significant diminishment. The son of the latter, the heraldist Stanisà Âaw Kazimierz Kossakowski, divided the estate among his three sons; however, it was largely lost due to confiscations following World War II.
Coat of arms of the Kossakowski family was à Âlepowron.