Bolesław IV of Warsaw
| Bolesław IV | |
|---|---|
Bolesław IV of Warsaw, 15th century | |
| Duke of Warsaw | |
| Reign | 8 December 1429 – 10 September 1454 |
| Predecessor | Janusz I |
| Successor | Bolesław V of Warsaw |
| Regent | Anna Feodorovna of Ratnie |
| Sovereign Duke of Podlachia | |
| Reign | 1440–1444 |
| Born | c. 1421 |
| Died | 10 September 1454 Opinogóra Górna |
| Burial | |
| Spouse | Barbara Aleksandrówna |
| Issue | Bolesław Janusz Konrad III Rudy Bolesław Casimir III of Płock Janusz Anna Sophia Bolesław V of Warsaw Janusz II of Płock |
| House | Piast dynasty |
| Father | Bolesław Januszowic |
| Mother | Anna Feodorovna of Ratnie |
Bolesław IV of Warsaw (Polish: Bolesław IV warszawski; c. 1421 – 10 September 1454), was a Polish prince and member of the House of Piast in the Masovian branch. He was Duke of Warsaw during 1429–1454 (under regency until 1436) and sovereign Duke of Podlachia in 1440–1444.
He was the second son of Bolesław Januszowic (in turn second son of Janusz I of Warsaw) and Anna Feodorovna of Ratnie, a daughter of Fedor Olgierdowicz who ruled part of Volhynia.