Kazimierz Siemienowicz

Kazimierz Siemienowicz (Latin: Casimirus Siemienowicz, Lithuanian: Kazimieras Simonavičius; born c. 1600 – c. 1651) was a general of artillery, gunsmith, military engineer, and one of pioneers of rocketry. Born in the Raseiniai region of the Grand Duchy of Lithuania, he served in the armies of the Polish–Lithuanian Commonwealth and of Frederick Henry, Prince of Orange, the ruler of the Dutch Republic. No portrait or detailed biography of him has survived and much of his life is a subject of dispute.

After contributing his expertise to several battles, Siemienowicz published Artis Magnae Artilleriae in 1650. This treatise, which discusses rocketry and pyrotechnics, remained a standard work in those fields for two centuries.