|Part of the Eastern Front of World War II|
Soviet troops enter Frauenburg, 9 February (?) 1945
|Nazi Germany||Soviet Union|
|Commanders and leaders|
| Friedrich Hossbach (Fourth Army until January 29)
Friedrich Müller (Fourth Army from January 29)
| Konstantin Rokossovsky
(2nd Belorussian Front)
(3rd Belorussian Front until February 18 - KIA that day)
(3rd Belorussian Front from February 19)
|Casualties and losses|
128 planes (According to Soviet information) 
The Heiligenbeil Pocket or Heiligenbeil Cauldron (German: Heiligenbeiler Kessel) was the site of a major encirclement battle on the Eastern Front during the closing weeks of World War II, in which the Wehrmacht's 4th Army was almost entirely destroyed during the Soviet Braunsberg Offensive Operation (13 March 1945 - 22 March 1945). The pocket was located near Heiligenbeil in East Prussia in eastern Germany (now Mamonovo, Kaliningrad Oblast), and the battle, part of a broader Soviet offensive into the region of East Prussia, lasted from 26 January 1945 until 29 March 1945.
Attack on East Prussia 
The Red Army's East Prussian Operation commenced on 13 January 1945 with the objective of rolling up the substantial German defences in East Prussia and cutting off the provincial capital of Königsberg. The Soviet forces were opposed by the German Army Group Centre, including the Fourth Army, under the command of General Friedrich Hossbach. While the 3rd Belorussian Front initially met strong resistance, the outnumbered German forces soon began to suffer serious ammunition shortages. Colonel-General Reinhardt, commander of Army Group Centre, warned of the seriousness of the situation as early as 19 January, but was not permitted to make a phased withdrawal.
The pocket forms 
To save his units from encirclement, Hossbach started to pull the Fourth Army back to the west in direct contravention of orders, abandoning the prepared defences around Lötzen on 23 January. By this time, Rokossovsky's 2nd Belorussian Front had already broken through on Hossbach's right; the Soviet 5th Guards Tank Army headed for the Baltic coast, cutting off most of East Prussia. Through a series of forced marches in atrocious winter weather, and accompanied by thousands of civilians, the Fourth Army moved towards Elbing, still held by the German Second Army, but found its path blocked by Soviet forces of the 48th Army to the east of the town.
An attack beginning on the night of 26 January initially resulted in lead elements of the 28th Jäger Division breaking through to Elbing, where they linked up with the 7th Panzer Division; however German forces were driven back during the next four days after the 48th Army had regrouped. Hossbach's units now found themselves pushed into a Kessel (pocket) with their backs to the Frisches Haff.
Hossbach was relieved of command on 29 January, and was replaced by Friedrich-Wilhelm Müller. His three corps were given an order to cease their breakout attempt on 30 January. Along with some units of Second Army, they found themselves encircled in the area of Heiligenbeil and Braunsberg; many of the civilians trapped with them attempted to escape across the frozen Haff to the Frische Nehrung and thence to Pillau or Danzig, reinforced paths marked by lamps having been constructed across the ice by Fourth Army's engineers.
As the Nazis had effectively forbidden their evacuation, East Prussia's civil population was undiminished when the Red Army attacked on 12 January 1945. The attack resulted in a mass flight westwards towards the coast. Many people were killed by Soviet troops or by the severe frost. At the coast, in particular in the harbour of Pillau, the German navy managed to evacuate tens of thousands of them over the Baltic sea, and encouraged the very fierce resistance on land, since every hour's delay to the Red Army meant the rescue of additional thousands of East Prussian old people, women and children.
Attempts to break through the German perimeter early in February were fought back, with the Fourth Army receiving heavy artillery support from the ships Admiral Scheer and Lützow, firing across the Haff from the Baltic towards the Frauenburg end of the pocket. Frauenburg itself was taken on February 9, in fierce fighting involving elements of the 170th Infantry Division. During one Soviet attack the 3rd Belorussian Front's commander, General Ivan Chernyakhovsky, was killed by a shell splinter near Mehlsack. His successor, Marshal Aleksandr Vasilevsky, having effectively contained the remains of the Army Group, concentrated on assembling reinforcements over the next month: the Germans, under the supervision of Major-General Karl Henke, continued to attempt resupply and evacuations of wounded along the Frische Nehrung, often at night to avoid air attack. A long, narrow corridor through to the besieged garrison of Königsberg was also maintained against the attacks of the 11th Guards Army through a joint effort by the garrison and by the Großdeutschland Panzergrenadier Division.
Though the German forces in East Prussia had no realistic hope of victory, and were severely short of manpower, ammunition, and fuel, they continued to offer strong resistance: the Red Army suffered extremely high casualties in the East Prussian Operation as a whole. Ad-hoc battle groups were often bolstered by civilians press-ganged into the Volkssturm, and many East Prussian villages and towns had been turned into fortified strongpoints, in addition to the substantial fortifications centred on Heilsberg. In part, the fighting was prolonged in order to keep open civilian escape routes; in any case, requests to evacuate the main body of the Fourth Army were refused by the German High Command. The Soviet attack, however, came tragically late for the remaining inmates of the Heiligenbeil concentration camp, along with other camps in the area: even as Hossbach's forces were attempting to break out of East Prussia, the prisoners were driven to the coast and massacred.
Destruction of the 4th Army 
The pocket was finally crushed in an operation lasting from 13 March - 29 March, officially known as the Braunsberg Offensive Operation, in preparation for the final assault on Königsberg,
The Red Army quickly moved to cut communication between the Kessel and Königsberg, their troops reaching the coastline about 5 miles from the city on 15 March. A crossing of the Frisching River was forced in a night attack on the night of 17–18 March, further rolling up German defences of the Kessel from the east. Clearer weather from 18 March allowed an intensive aerial bombardment of the Fourth Army's positions.
With most communications cut, German forces remaining in the pocket were now faced with either death or being taken prisoner. Some 'elite' units, such as the Fallschirm-Panzergrenadier Division 2 Hermann Göring and the 24th Panzer Division, were evacuated by sea, but others were gradually cut off in a series of small pockets on the coast, in some cases actually digging into the coastal embankments or beaches. POW reports suggested that many German units were now seriously understrength, with the 50th Infantry Division, for example, able to field only a single incomplete regiment.
The Soviets finally took Braunsberg on 20 March. Heiligenbeil, covering the small port of Rosenberg, was attacked with phosphorus bombs on 22 March and successfully stormed on 25 March, the town suffering almost complete destruction. Rosenberg itself was taken on 26 March, with the remnants of the Fourth Army falling back on the Kahlholzer Haken peninsula, where the perimeter was defended by troops from the Panzerkorps "Großdeutschland" and the 28th Jäger Division. The last evacuations took place on the morning of 29 March from Kahlholz and Balga, where a remnant of the 562nd Volksgrenadier Division was destroyed forming a rearguard (its commander, Helmuth Hufenbach, receiving a posthumous promotion to Major-General). Soviet sources claimed 93,000 enemy dead and 46,448 taken prisoner during the operation; German sources claim that many troops in the Kessel were successfully evacuated to the Frische Nehrung. Given the chaos prevailing at this stage of the war, it is unlikely that accurate figures will ever be determined, many soldiers having simply disappeared. Further elements of the Fourth Army continued to resist around Pillau, and latterly on the Frische Nehrung, until May.
Red Army 
The following Soviet units were involved in completing the encirclement of the Kessel:
- 2nd Belorussian Front (Marshal Konstantin Rokossovsky)
- 3rd Belorussian Front (General Aleksandr Vasilevsky)
German records list the following units with the Fourth Army at the time of the Kessel's collapse:
- VI Corps (General Horst Großmann)
- XX Corps (General Rudolf Freiherr von Roman)
- XXXXI Panzer Corps (General Helmuth Weidling)
- 50th Infantry Division
Nearly all German units would have been at well below divisional strength even at the start of the East Prussian Operation; also some additional units involved (such as the 299th Infantry Division and 18th Panzergrenadier Division) were destroyed, disbanded or completely evacuated before the Kessel collapsed.
- Beevor, Antony. Berlin: The Downfall 1945, Penguin Books, 2002, ISBN 0-670-88695-5
- Duffy, Christopher. Red Storm on the Reich: The Soviet March on Germany, 1945, Routledge, 1991, ISBN 0-415-22829-8
- Hastings, Max. Armageddon: The Battle for Germany, 1944-1945, Macmillan, 2004, ISBN 0-333-90836-8
- Lanza, Conrad. Perimeters in Paragraphs, Field Artillery, May 1945
-  German-language article on Palmnicken massacre at shoa.de. Retrieved June 22, 2007.
- Duffy, p.172
- Duffy, p.173
- Though many accounts describe the Wehrmacht assisting civilians in escaping East Prussia, others describe civilians being forced off the road along the Frische Nehrung to make way for military traffic, and male refugees being compelled to join Volkssturm units (see accounts in Hastings, Chapter 10).
- Duffy, p.204
- See RIA Novosti archives
- Duffy, pp.161-2
- Official Soviet figures gave a total of 584,788 casualties for the entire area of the offensive during the period from 13 March - 25 April.
- Hastings, p.307
- Lanza, p.274
- Duffy, p.205
- See RIA Novosti archives
- Duffy, p.206
- Future German President Richard von Weizsäcker was amongst the military personnel on the final boats from Balga.
- Meier-Welcker, in Die Abwehrkämpfe am Nordflügel der Ostfront 1944-45, states that 57,585 troops and a further 70,535 wounded were evacuated from Rosenberg and Balga after 13 April (pp. 374-5). Soviet figures from Duffy, p.206
- Koenigsberger Express Das Niemandsland gibt ein Geheimnis preis. Koenigsberger Express, ed. 2004/7