He was the third son of Duke Wenceslaus I of Zator by his wife Maria, daughter of Urban Kopczowski, a noblemen from the Duchy of Siewierz. At the time of his father"s death in 1468, January V and his brother Władysław were likely minors, so their older brothers Casimir II and Wenceslaus II assumed the government over the Duchy.
lieutenant can also refer to January V van Virneburg and to January V of Nassau-Vianden-Diez. The common government of Wenceslaus I"s sons lasted until 1474, when was made the formal division of the Duchy in two parts: January V, together with Władysław, received the western part of Skawa River. Despite this, January V entered in conversations with Duke Casimir II of Cieszyn, and also signed with him an inheritance treaty.
However, this agreement was null because didn"t count with the approval of the Dukes of Zator"s sovereign, King Casimir IV of Poland.
By 18 May 1477, January V married with Barbara (ca 1452/53 – bef 12 May 1507), daughter of Duke Bolesław II of Cieszyn and widow of Duke Balthasar of Żagań. They had no children.
In 1482 January V and Władysław made the division of their small Duchy between them. Władysław received a monetary compensation and the town of Wadowice, who was ruled by him until his death in 1494.
Since then the formal owner of the Duchy was Poland, but January V retain his title and owned several properties in the area, were continue to live.
As an additional salary, January V received 200 fines per year as an income from the salt mines of Wieliczka. January V died on 17 September 1513, murdered by a wealthy Polish nobleman, Wawrzyniec Myszkowski. The reason for the murder was very banal: water from the pond in Myszkowski"s lands, who was given free to the townspeople by January V"s orders, resulting in a significant financial loss to Myszkowski.
January V was buried in Zator, although it"s unknown in which of the parish churches.
Zator was formally annexed to the Polish crown on 26 October of that year, when the Starost of Oświęcim, Andrzej Kościelecki, received from the local nobility the oath of loyalty to the Polish King. January V leave an illegitimate son, also called January (ca 1500 – bef 14 August 1521), who, after the death of his father, was placed under the care of the Starost Kościelecki by orders of King Sigismund I the Old, in whose court January was educated.
On 18 June 1518 January is certified as a guest at the wedding of King Sigismund with Bona Sforza. He probably died some time later, between 1519–1521 unmarried and childless.
