Gustav I of Sweden in the context of "Gripsholm Castle"

Plate armour is a historical type of personal body armour made from bronze, iron, or steel plates, culminating in the iconic suit of armour entirely encasing the wearer. Full plate steel armour developed in Europe during the Late Middle Ages, especially in the context of the Hundred Years' War, from the coat of plates (popular in late 13th and early 14th century) worn over mail suits during the 14th century, a century famous for the Transitional armour, in that plate gradually replaced mail.

In Europe, full plate armour reached its peak in the 15th and 16th centuries. The full suit of armour, also referred to as a panoply, is thus a feature of the very end of the Middle Ages and the Renaissance period. Its popular association with the "medieval knight” is due to the specialised jousting armour which developed in the 16th century.

The House of Vasa or Wasa was a royal house that was founded in 1523 in Sweden. Its members ruled the Kingdom of Sweden from 1523 to 1654 and the Polish–Lithuanian Commonwealth from 1587 to 1668. Its agnatic line became extinct with the death of King John II Casimir Vasa in 1672.

The Vasa dynasty descended from a 14th-century Swedish noble family, tracing agnatic kinship to Nils Kettilsson (Vasa) (d. 1378), the fogde of Tre Kronor Castle in Stockholm. Several members held high offices during the 15th century. In 1523, after the Stockholm bloodbath and the abolition of the Kalmar Union, Gustav Eriksson (Vasa) became King Gustav I of Sweden and the royal house was founded. His reign is sometimes referred to as the beginning of the modern Swedish state, which included the King's break with the Catholic Church during the Protestant Reformation and the foundation of the Church of Sweden.

The Reformation in Sweden is generally regarded as having begun in 1527 during the reign of King Gustav I of Sweden, but the process was slow and was not definitively decided until the Uppsala Synod of 1593, in the wake of an attempted Counter-Reformation during the reign of John III (1568–1592).

The Swedish Reformation caused the Church of Sweden to break with the Roman Catholic Church. It is considered to mark the end of the Swedish Middle Ages. The Reformation resulted in both Sweden and Finland becoming Protestant countries, as the latter formed an integral part of Sweden at the time.