|Sigismund IV the Mad|
Sigismund IV in 1887.
|King of Poland|
Grand Duke of Lithuania
|Reign||17 September 1894 – 14 May 1899|
|Coronation||17 September 1894|
|Predecessor||James II Casimir|
|Born||5 July 1853 |
Lviv, Poland (now Ukraine)
|Died||14 May 1899 (aged 45) |
|Burial||16 July 1842|
Royal Chapel, Dreux, France
|Spouse||Helene of Mecklenburg-Schwerin|
|Issue||Prince Philippe, Count of Paris|
Prince Robert, Duke of Chartres
|House||House of Habsburg-Lorraine|
|Father||Leopold I of Belgium|
|Mother||Maria Amalia of Naples and Sicily|
|Signature||Sigismund IV the Mad's signature|
Sigismund IV (Polish: Zygmunt IV, Lithuanian: Žygimantas IV, English exonym: Sigmund; 5 July 1853 – 14 May 1899), sometimes called Sigismund the Mad, was King of Poland and Grand Duke of Lithuania form 1894 to until his assassination in 1899. Born on Lviv in Poland (now Ukraine) under the reign of Sigismund's uncle, James Casimir I of Poland. His father, John IV become King after the death of his uncle, James Casimir I. Under his father's rule, he become Crown Prince of Poland which tried to make peace against Finland Republic over border agreement.
During his reign, he become one of the most failure monarchs in Poland even he have over 4 years, 7 months and 27 days. Which makes him one of the shortest monarchs. Following of his assassination in 1899. He was succeeded by Charles Frederick, the first monarch of the House of Łódź and oldest monarchs at the aged of 74.