Tags: Noble.
Euphemia of Masovia (Polish: Eufemia mazowiecka; 1395/97 – before 17 September 1447) was a Polish princess a member of the House of Piast in the Masovia branch and by marriage Duchess of Cieszyn.She was the fifth child and third daughter of Siemowit IV Duke of Masovia by his wife Alexandra daughter of Algirdas Grand Duke of Lithuania and sister of King Władysław II Jagiełło of Poland.