Daugavgrīva Castle was originally a monastery converted as a fortress by Swedish in the 17th century. Today there are no remnants of the medieval castle above the soil.
In 1208 there was a Dünaburg castle built by the Teutonic Knights which initially served as a monastery. The Swedish fortress of Dünamünde, designed in a Dutch style by General Rothenburg in 1641, replaced the ruined Daugavgrīva Castle by 1680. In 1695 the Commandant was captain Heinrich Nicolaus Rüdinger, forefather of future Patriarch Alexy II of Russia. Rüdinger was knighted by Charles XI of Sweden. Joachim Cronman later became the Commandant and he died on March 5, 1703.
After the fortress was seized by the Russians they reconstructed it. Regent Anna Leopoldovna of Russia, her husband Anthony Ulrich, and her son Ivan VI were incarcerated in Dünamünde in 1742. A local Lutheran church was rebuilt into the Orthodox Church of the Saviour's Transfiguration in 1775. The Russian government renamed the fortress, where only Russian soldiers were living, to Ust-Dvinsk in 1893. They had its fortifications completely reconstructed prior to World War I. During the war Ust-Dvinsk was bombarded by the Schütte-Lanz Airship SL 7 of the German Army. After the fortress was taken by Imperial Germany, it was inspected by Emperor Wilhelm II in 1917. The Latvian government, however, demolished much of the fortifications several years later. During the Cold War Ust-Dvinsk was a base for Soviet troops. The site is now known in Latvian as Daugavgrīva. There is a functional lighthouse at Daugavgrīva which was originally built in 1818. It was rebuilt in 1863, 1920, and after World War II.
Nowadays entrance in the area of castle goes along the northeastern corner. Still there is partly visible the old road which was leading from northeastern tower around the forepart of the castle up to the southeastern corner.References:
The famous Italian Medici family have given two queens to France: Catherine, the spouse of Henry II, and Marie, widow of Henry IV, who built the current Luxembourg palace. Maria di Medici had never been happy at the Louvre, still semi-medieval, where the fickle king, did not hesitate to receive his mistresses. The death of Henry IV, assassinated in 1610, left the way open for Marie's project. When she became regent, she was able to give special attention to the construction of an imposing modern residence that would be reminiscent of the Palazzo Pitti and the Boboli Gardens in Florence, where she grew up. The development of the 25-hectare park, which was to serve as a jewel-case for the palace, began immediately.
The architect, Salomon de Brosse, began the work in 1615. Only 16 years later was the palace was completed. Palace of Luxembourg affords a transition between the Renaissance and the Classical period.
In 1750, the Director of the King's Buildings installed in the wing the first public art-gallery in France, in which French and foreign canvases of the royal collections are shown. The Count of Provence and future Louis XVIII, who was living in Petit Luxembourg, had this gallery closed in 1780: leaving to emigrate, he fled from the palace in June 1791.
During the French Revolution the palace was first abandoned and then moved as a national prison. After that it was the seat of the French Directory, and in 1799, the home of the Sénat conservateur and the first residence of Napoleon Bonaparte, as First Consul of the French Republic. The old apartments of Maria di Medici were altered. The floor, which the 80 senators only occupied in 1804, was built in the middle of the present Conference Hall.
Beginning in 1835 the architect Alphonse de Gisors added a new garden wing parallel to the old corps de logis, replicating the look of the original 17th-century facade so precisely that it is difficult to distinguish at first glance the old from the new. The new senate chamber was located in what would have been the courtyard area in-between.
The new wing included a library (bibliothèque) with a cycle of paintings (1845–1847) by Eugène Delacroix. In the 1850s, at the request of Emperor Napoleon III, Gisors created the highly decorated Salle des Conférences, which influenced the nature of subsequent official interiors of the Second Empire, including those of the Palais Garnier.
During the German occupation of Paris (1940–1944), Hermann Göring took over the palace as the headquarters of the Luftwaffe in France, taking for himself a sumptuous suite of rooms to accommodate his visits to the French capital. Since 1958 the Luxembourg palace has been the seat of the French Senate of the Fifth Republic.