The palace was founded by Ernst Biron on a flat island between the Lielupe River and its tributaries in 1738. Construction took place on the site of the dismantled residence of the former Dukes of Courland from the Kettler dynasty, which was preceded by a medieval castle of the Livonian Order. At the same time, Rastrelli was designing Biron's country residence in Rundāle.

Due to Biron's disgrace in 1740, all construction work was halted, although the palace had not yet been roofed. Construction resumed after Biron's return from exile in 1763. Besides Rastrelli, after the death of his patroness Elizabeth and losing commissions in St. Petersburg, the Danish architect Severin Jensen was involved in completing the ducal residence, giving it some classical features.

After the completion of construction in 1772, the elderly duke lived in the Mitava Palace for less than six months. In 1779, his successor, Peter Biron, hosted the famous Count Cagliostro at the palace. After the duchy's annexation by Russia in 1795, the Mitava Palace frequently changed owners. For many years, it provided refuge to aristocrats fleeing revolutionary France, including Louis XVIII and his family from 1798 to 1800. It was also here that Marie Thérèse of France married the Duke of Angoulême.

The Mitava Palace is not generally considered one of Rastrelli's artistic successes. Literature notes the dry monotony of the facade design, which lacks the rhythmic variety and plastic richness characteristic of Rastrelli's buildings from the Elizabethan era. Instead of a longitudinal emphasis, the architect shifts the focus to a transverse axis of symmetry. Also atypical for Rastrelli, the palace in Jelgava lacks a palace park, and the perspective of the main courtyard is not enclosed but opens onto the city panorama. In the post-war period, only elements of the exterior decoration were restored.

No detailed information has survived about the original interiors of the Mitava Palace. Apparently, festoons, masks, and stucco details intended for the Rundāle residence were used in the facade decoration. Much in the decorative design of these palaces is similar.

Abbot Georgel visited Mitava in December 1799. Here is what he wrote:

"The castle, formerly the residence of the Dukes of Courland, stands on the edge of the town on the Riga road, on the left bank of the Grosbach River (Big Stream). This castle, surrounded by a moat filled with water, forms a large square with four facades and a courtyard in the middle. It is built in the style of contemporary buildings and has a very impressive appearance: the part damaged by fire has been rebuilt. The St. Petersburg court, having rightfully annexed the two duchies—Courland and Semigallia—to its empire, apparently intends to turn this castle into a barracks. The interior chambers are large, spacious, and worthy of a royal personage: at this moment, the castle served as a refuge for Louis XVIII, generously granted to him by Paul I, where he took shelter with his entire current court."

In October 1804, gunpowder stocks stored in the Jelgava Palace cellar since ducal times were transported to Riga. There were about 350 kg of gunpowder in total. A document dated October 10, 1804, survives in which Count Arakcheev, then the general inspector of all artillery of the Russian army and commander of the Life Guards Artillery Battalion, sent a letter to the Riga military governor, Count Buxhoeveden, stating that 16 poods of gunpowder were ordered to be received by the Riga citadel artillery team. About 88 kg of gunpowder from the Jelgava Palace arsenal were intended for the Mitava provincial company.

In 1812, German troops from Prussia, conquered by Napoleon, invaded Courland. They occupied Bauska and Jelgava. The occupiers planned to restore the Duchy of Courland and annex it to Prussia. During the occupation of Mitava by Napoleon's army, starting from July 1812, Napoleonic soldiers set up a hospital in the Great Hall and several ceremonial rooms on the palace's third floor, which continued to operate for some time after the war ended, now serving sick and wounded Russian soldiers.

The palace's interior decoration, on which Barizien, Johann Michael Graff, and the Italian painter d’Angeli worked by Biron's order, was destroyed in 1918 when the Mitava Palace was looted and burned by the retreating Bermondt-Avalov forces. It was restored for the needs of a future university during independent Latvia in 1936–1939; at that time, a laboratory building was erected on the site of the former stables, thus closing the courtyard square on the city side. In 1937, the western wing was added to the palace according to the design of architect E. Laube.

In 1939, the Jelgava Agricultural Academy moved into the palace.

The palace suffered even more damage during the military actions of 1944. The restoration carried out also for the needs of the recovering university in 1956–1964 practically did not affect the interiors. In 1961, the Latvian Agricultural Academy moved into the building, now the Latvia University of Life Sciences and Technologies.

On January 29, 2024, a fire broke out in the palace attic; university staff were evacuated, and firefighters are inspecting the premises and determining the fire source.

The greatest historical interest lies in the Courland Dukes' Mausoleum — a crypt on the southeast side of the basement floor, arranged in 1820. Before 1820, burials were located in the castle; during wartime, the sarcophagi were repeatedly looted.

Inside the mausoleum are 30 sarcophagi, 24 metal and 6 wooden, made for the dukes of the Kettler family from 1569 to 1743. The crypt contains the remains of Gotthard Kettler, the 1st Duke of Courland and the last Master of the Livonian Order; Jacob Kettler, Duke of Courland, their spouses, and children.

Sources:

https://ru.wikipedia.org/wiki/Митавский_дворец

https://www.castle.lv/latvija/jelgava2.html
Project by Rinata Rimsha