Treaty of Oliwa was signed: It was one of the peace treaties which ended the Second Northern War (1655-1660) between Sweden, the Polish-Lithuanian Commonwealth, the Habsburgs and Brandenburg-Prussia. The terms of the treaty included the renunciation by John II Casimir to his claims of the Swedish crown (which his father Sigismund III Vasa had lost in 1599). Poland also formally ceded to Sweden, Livonia and the city of Riga, which had been under Swedish control since the 1620s. The treaty settled conflicts between Sweden and Poland left standing since the War against Sigismund (1598-1599), the Polish-Swedish War (1600-1629), and the Northern Wars (1655-1660).
The April Constitution of Poland was the general law passed by the act of the Polish Sejm on April 23, 1935. It introduced a presidential system of government with certain elements of authoritarianism. It was accepted in violation of the earlier March Constitution of 1921 and the Rules of the Parliament, and as such it was questioned by most of the opposition to the rule of Sanacja. (Sanacja, or Sanation was created in the interwar period, prior to Józef Piłsudski's May 1926 Coup d'État, and came to power in the wake of that coup.)
The Polish Sejm declared November 11 as the National Independence Day. It was celebrated only twice before World War II broke out. After the war, the communist regime of the People's Republic removed Independence Day from the calendar. Even so, the Polish people continued to celebrate it informally. The Soviets officially replaced National Independence Day, with the "National Day of Poland's Revival as Poland's National Day" celebrated on the July 22, the anniversary of the communist PKWN Manifesto under Joseph Stalin. When Poland emerged from communism in 1989, the original holiday, National Independence Day, on November 11th, was finally restored.
The race to Berlin ended with the Soviet arrival into the capital first. The Soviet 1st Belorussian Front and 1st Ukrainian Front continued to tighten the encirclement and severing the last link between the German IX Army and the city. Elements of the 1st Ukrainian Front continued to move westward and started to engage the German XII Army moving towards Berlin. By the next day elements of 1st Belorussian Front and 1st Ukrainian Front had completed the encirclement of the city. On April 25th, the Soviet investment of Berlin had been consolidated, with leading Soviet units probing and penetrating the S-Bahn defensive ring. It became clear that the German defence of the city could not do anything but temporarily delay the capture of the city by the Soviets. The decisive stages of the battle had already been fought and lost by the Germans outside the city. 1,100,000 Soviet personnel who took part in the capture of Berlin from April 22 to May 2, 1945 (Note: Poland's official Flag Day is held each year on 2 May, the last day of the battle in Berlin, when a solider of the Polish Army hoisted the Polish flag on the Berlin Victory Column.)
Hermann Göring sent a message to Hitler asking for permission to assume leadership of the Third Reich. Interpreting the telegram as an act of treason, Hitler relieved Göring of his official titles and ordered his arrest. The message was translated to English, as follows: "My Fuhrer, General Koller today gave me a briefing on the basis of communications given him by Colonel General Jodl and General Christian, according to which you had referred certain decisions to me and emphasized that I, in case negotiations would become necessary, would be in an easier position than you in Berlin. These views were so surprising and serious to me that I felt obligated to assume, in case by 2200 o’clock no answer is forthcoming, that you have lost your freedom of action. I shall then view the conditions of your decree as fulfilled and take action for the well being of Nation and Fatherland. You know what I feel for you in these most difficult hours of my life and I cannot express this in words. God protect you and allow you despite everything to come here as soon as possible. Your faithful Hermann Göring" On April 25, Hitler issued a telegram to Göring telling him that he had committed "high treason" and gave him the option of resigning all of his offices in exchange for his life. Shortly thereafter, Bormann ordered the SS in Berchtesgaden to arrest Göring. When Hitler discovered, on April 28, that Heinrich Himmler was trying to discuss surrender terms with the western Allies, he ordered Himmler's arrest and had Hermann Fegelein (Himmler's SS representative at Hitler's HQ in Berlin) shot.
In one of the rare actions of the Pacific War that involved a German submarine, U-183 was sunk off the southern coast of Borneo by the American submarine Besugo. After having served in the Battle of the Atlantic, U-183 sailed from France in July 1943, arriving at Penang on October 27. She operated in that zone for almost two years and carried out six war patrols. On April 23, 1945, just days before Germany's surrender, she was attacked and sunk in the Java Sea by American submarine Besugo (SS-321). Only one crew member survived.
Members of the 358th and 359th U.S. Infantry Regiments liberated Flossenbürg on April 23, 1945. Flossenburg was a Nazi German concentration camp built in May 1938 in Bavaria, Germany, near the border with Czechoslovakia. Before its liberation, more than 96,000 prisoners passed through the camp, around 30,000 of whom died. An American military tribunal tried 46 former staff from Flossenbürg concentration camp for crimes of murder, torture, and starving the inmates in their custody. All but 5 of the defendants were found guilty, 15 of whom were condemned to death, 11 were given life sentences, and 14 were jailed for terms varying from 1 to 30 years.