Zbigniew Oleśnicki, Polish cardinal and statesman (born 1389)

Zbigniew Oleśnicki, known in Latin as Sbigneus, was a high-ranking Roman Catholic clergyman and an influential Polish statesman and diplomat. He served as Bishop of Kraków from 1423 until his death in 1455. He took part in the management of the country's most important affairs, initially as a royal secretary under King Władysław II Jagiełło and later as the effective regent during King Władysław III's minority. In 1439 he became the first native Polish cardinal.

April 1 is the 91st day of the year in the Gregorian calendar; 274 days remain until the end of the year.