The site of the castle was first referred to as Gripsholm (Grip’s Island) in 1381. Bo Jonsson Grip died in 1386, and Gripsholm passed through various hands over the course of the following century. Eventually it was donated to the Carthusian order of monks, who established a monastery nearby which they named Pax Mariæ — Peace of Mary, or Mariefred.

Less than three decades later, the monastery was abolished by King Gustav Vasa (Gustav I) during the Reformation, its property claimed by the Swedish state. Gustav Vasa also ordered the demolition of Grip’s original fortress and the construction of a new Renaissance castle for residential and defense purposes. The main castle was completed by 1545, but additions and improvements continued to be made throughout Gustav Vasa’s reign and during the reign of his eldest son Erik XIV, who succeeded to the throne in 1560. A good example of how Gripsholm would have appeared during this period is the Hall of State, which has a painted ceiling and portraits of Gustav Vasa and other European regents of the time.

Erik XIV’s reign was marked by conflict with his half-brother Johan, Duke of Finland, married to the Polish princess Katarina Jagellonica. In 1563, Erik had Johan and Katarina imprisoned in Gripsholm Castle, where they remained for four years. Their two eldest children, Isabella and Sigismund (later King of Sweden and Poland), were born at Gripsholm during this period of captivity.

In 1568 it was Erik’s turn to be imprisoned after alienating the nobility and displaying increasing signs of mental illness. Dethroned by his brother, who became King Johan III, Erik was moved from castle to castle during his captivity, which included 19 months at Gripsholm. He ultimately died in prison at Örbyhus Castle in Uppland, reputedly by order of Johan. (According to historical tradition, Erik was poisoned with arsenic served to him in a bowl of pea soup.)

Gustav Vasa’s youngest son, Duke Karl — who later overthrew his nephew Sigismund and claimed the Swedish throne for himself as Karl IX — also made various modifications to Gripsholm. His bedroom, known as Duke Karl’s Chamber, is considered one of the best examples of a 16th-century interior in Sweden.

During Sweden’s Age of Great Power, Gripsholm was home to the dowager queens Maria Eleonora (the widow of Gustav II Adolf, who was killed in battle in 1632) and Hedvig Eleonora (the widow of Karl X, who died in 1660). Hedvig Eleonora was responsible for significant renovations and additions to the castle. She also had a strong interest in art and added some 200 portraits to Gripsholm’s collection, some of which are on display in her apartments on the ground floor.

Under Gustav III, Gripsholm experienced a new heyday in the late 18th century. Known as the Theater King, Gustav spent extensive time at Gripsholm along with much of his court. Among other modifications he had a royal theater installed in one of the castle’s round towers. Inaugurated in the spring of 1782, it’s considered one of Europe’s best-preserved 18th-century theaters.

Gustav III was assassinated in 1792 — shot at a masquerade ball in Stockholm, he clung to life for nearly two weeks before succumbing to his wounds — and was succeeded by his 13-year-old son, Gustav IV Adolf, whose hostile attitude towards revolutionary and Napoleonic France, combined with an unrealistic belief in his own kingdom’s military strength, drew Sweden into wars it could not win, leading to a military coup that deposed Gustav Adolf in 1809. He and his family spent nine months at Gripsholm under house arrest before going into exile, never to return to Sweden.

During the 19th century Gripsholm came to be viewed as a national monument. In the late 1800s, a somewhat controversial effort was made to restore the castle as much as possible to its Renaissance appearance.