Krustpils Castle (Kreutzburg) is one of the best preserved medieval castles in Latvia. The first written reference of the Krustpils dates from 1237, when the Archbishop of Riga built a castle named Kreutz. In 1359, the Livonian order took seven castles belonging to the Riga Archbishopric, being Krustpils among them. During the Livonian war in 1559 the castle was devastated.
When the Livonian state was dissolved, Krustpils became property of the Polish-Lithuanian Commonwealth from 1561 to 1772, while the opposite Jēkabpils was part of the Duchy of Courland and Zemgale. The difference between the Latgalian language and the Selonian dialect of the inhabitants on either side of the Daugava River remains as of today. In 1585,Stephen Báthory of Poland granted a large area which included Krustpils to general Nikolai von Korff, whose family owned the castle until the Latvian agrarian reforms of 1920 came into effect. As Krustpils castle became a residence of landlords, it gradually lost its medieval character.
In the 18th century the castle got a representative look when Baroque elements were added to exterior of the castle. At the time of the Russo-Turkish War from 1877 to 1878, there was a camp for Turkish prisoners of war, many of whom settled here permanently.
Krustpils castle together with other buildings of this complex was transferred to the Latvian army after 1920 and the Latgale artillery regiment was located there. During the Second World War infirmary of the German army was located there. The Military hospital of the Red Army was placed to Krustpils after August 1944.
During the Soviet times regiments of Soviet army were located in the castle such as the 16th regiment of long-range intelligence aviation and main storehouses of the 15th air regiment. For 50 years the premises were not managed and were close to be considered as ruins. After 1991 there has been ongoing active investigation and renewal of the castle.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.