Jakub of Sienno was a medieval Bishop of Kraków in the years 1461–1463, Bishop of Włocławek from 1464, and then Archbishop of Gniezno from 1474. He was also a 15th-century diplomat for the Polish Crown.
- Occupation
- Catholic priest, Catholic bishop
- Position held
- king's secretary at the Polish court, Roman Catholic Bishop of Włocławek, bishop of Krakow, Roman Catholic Archbishop of Gniezno
- Citizenship
- Poland
- Born
- 1413
- Died
- October 4, 1480
