Family

John married his first wife, Catherine Jagellonica of Poland (1526–83), house of Jagiello, in Vilnius

Vilnius

Vilnius is the capital of Lithuania, and its largest city, with a population of 560,190 as of 2010. It is the seat of the Vilnius city municipality and of the Vilnius district municipality. It is also the capital of Vilnius County...

 on 4 October 1562. In Sweden, she is known as Katarina Jagellonica. She was the sister of king Sigismund II Augustus of Poland

Sigismund II Augustus

Sigismund II Augustus I was King of Poland and Grand Duke of Lithuania, the only son of Sigismund I the Old, whom Sigismund II succeeded in 1548...

. Their children were:

• Isabella (1564–66)
• Sigismund
  Sigismund III Vasa
  Sigismund III Vasa was King of Poland and Grand Duke of Lithuania, a monarch of the united Polish–Lithuanian Commonwealth from 1587 to 1632, and King of Sweden from 1592 until he was deposed in 1599...
  
   King of Sweden (1592–99), and King of Poland (1587–1632), Grand Duke of Finland and Lithuania
• Anna
  Anna of Finland
  Anna Vasa or Anna of Sweden also Anne was a Swedish princess. She was the sister of the monarch of Poland, Sweden and Lithuania, Sigismund III Vasa, and starosta of Brodnica and Golub.-Biography:...
  
   (1568–1625)

He married his second wife Gunilla Bielke

Gunilla Bielke

Gunilla Bielke; full name: Gunilla Johansdotter Bielke , was Queen of Sweden, the second spouse and queen consort of king John III of Sweden...

 (1568–c. 1592) on 21 February 1584; they had a son:

• John (Johan)
  John, Duke of Ostrogothia
  John of Sweden, Duke of Östergötland was a Swedish royal dynast...
  
   (1589–1618), firstly Duke of Finland
  Duke of Finland
  Duke of Finland was an occasional medieval title granted as a tertiogeniture to the relatives of the King of Sweden between the 13th and 16th centuries. It included a duchy along with the feudal customs, and often meant a veritably independent principality...
  
  , then from 1608 Duke of Ostrogothia. The young duke married his first cousin
  Cousin marriage
  Cousin marriage is marriage between two cousins. In various jurisdictions and cultures, such marriages range from being considered ideal and actively encouraged, to being uncommon but still legal, to being seen as incest and legally prohibited....
  
    Maria Elisabet
  Princess Maria Elizabeth of Sweden
  Princess Maria Elizabeth of Sweden, , was a Swedish princess, daughter of king Charles IX of Sweden and Christina of Holstein-Gottorp, and by marriage duchess of Ostrogothia....
  
   (1596–1618), daughter of Charles IX of Sweden
  Charles IX of Sweden
  Charles IX of Sweden also Carl, was King of Sweden from 1604 until his death. He was the youngest son of King Gustav I of Sweden and his second wife, Margaret Leijonhufvud, brother of Eric XIV and John III of Sweden, and uncle of Sigismund III Vasa king of both Sweden and Poland...
  
   (reigned 1599–1611)

Together with his mistress Karin Hansdotter

Karin Hansdotter

Karin Hansdotter was the royal mistress of King John III of Sweden in the 1550s before his marriage during his time as Prince and Duke of Finland.- Biography :...

 (1532–96) he had at least four illegitimate children:

• Julius Gyllenhielm (1559–81)
• Augustus (1557–60)
• Sofia
  Sofia Johansdotter Gyllenhielm
  Sofia Johansdotter Gyllenhielm in Reval, Estonia, was a Swedish noble. She was the illegitimate daughter of King John III of Sweden and Karin Hansdotter....
  
   (1556–83), who married Pontus De la Gardie
  Pontus De la Gardie
  Pontus De la Gardie was a French nobleman and general in the service of Denmark and Sweden.He was born Ponce De La Gardie in Russol , Languedoc, as a son of Jacques De la Gardie and Catherine de Sainte-Colombe. As a youngster, he wanted to become a priest and was educated in a monastery...
  
  
• Lucretia (1560–85)

John cared for Karin and their children even after he married Catherine Jagellonica, in 1562. He got Karin a husband that would care for her and the children: in 1561, she married the nobleman Klas Andersson (Västgöte), a friend and servant of John. They had a daughter named Brita. He continued supporting Karin and his illegitimate children as a king, from 1568. In 1572 Karin married again, as her first husband was murdered by Erik XIV in 1563, to a Lars Henrikson, whom John ennobled in 1576 to care for his issue with Karin. The same year, he made his daughter Sofia a lady in the castle, as a servant to his sister Princess Elisabet

Princess Elizabeth of Sweden

Princess Elizabeth of Sweden, , was a Swedish princess and a duchess consort of Mecklenburg-Gadebusch...

. In 1580, John married her to Pontus de la Gardie. She later died giving birth to Jacob De la Gardie

Jacob De la Gardie

Field Marshal and Count Jacob Pontusson De la Gardie was a statesman and a soldier of the Swedish Empire....

.