John III of Sweden was a king who ruled from 1568 to 1592. He was born on December 20, 1537, and was the son of Gustav I of Sweden, the founder of the modern Swedish state. John III is known for his efforts to strengthen the monarchy and for his attempts to promote the Lutheran faith in Sweden. During his reign, John III faced challenges from both internal factions and external threats, particularly from Denmark. He is also remembered for his cultural contributions, including the establishment of the Uppsala University and the promotion of arts and literature in Sweden.