Despite his widely acknowledged success, which almost resulted in the Allies being pushed back into the sea, Sieckenius was made a scapegoat and sidelined until his death during the Battle of Berlin, when he commanded the 391st Wehrmacht security division.

Through maternal lineage, he was a cousin to General Heirnrich von Prittwitz und Gaffron, whose grandmother, Maria Camilla Rittner, was a sibling of Sieckenius's grandfather.

Despite the reported debts amounting to 340,000 Reichsmarks, Sieckenius and his brothers continued their costly Gymnasium education in Bunzlau until 1914, when the war interrupted the summer vacation.

18-year-old Sieckenius and his elder brother Otto-Heinrich joined up immediately on 22 August 1914 as Kriegsfreiwilliger, both enlisting in the Feldartillerie Regiment Nr.5, with which he served in the Russian front.

In November 1915, he was transferred as corporal to the 154th Infantry Regiment in France, serving successively as a platoon leader, company commander, and battalion adjutant.

(May 8, 1917, Battle of Winterberg)After Germany's defeat, Sieckenius volunteered to join Freikorps Regiment Graf Yorck of the Border Guard (Grenzschutz).

A keen sportsman, Sieckenius became the chairman of “Elberfeld-Barmen Police Sports Club” in 1923, attended physical fitness and riding training schools, and often appeared in local newspapers on equestrian events.

On creation of the armored troops in late 1935, he transferred into the Panzer branch and was appointed a company commander in Panzer-Regiment 2 under his cousin Heirnrich von Prittwitz und Gaffron.

Oberstleutnant Sieckenius remained in command of a Panzer battalion and took part in the Battle of France.He received wound on the right leg on 18 May 1940 after days of intensive fighting without proper food and sleep, which was vividly accounted in his own combat report.

From May 1941 Sieckenius commanded Panzer-Regiment 2 of 16th Panzer Division under Generalmajor Hube, with which he took part in Operation Barbarossa, the invasion of the Soviet Union in June 1941.

On 12 April 1942, he received the following assessment from General of the Infantry Gustav von Wietersheim, commander of the XIV Panzer Corps: "Particularly valuable personality as a man and soldier.

By the time of the Battle of Kalach in early August, the 16th Panzer Division had already destroyed 1,000 tanks on the Eastern Front, mostly credited to Sieckenius’regiment.

On 23 August, the 16th Panzer Division carried out a 60-kilometer assault directly to the Volga River, with Kampfgruppe Sieckenius as the armored spearhead.

By 6:35 p.m., the leading tanks of the division had reached the western bank of the Volga, north of Stalingrad - marking the first time German forces had arrived at this fateful river.

Hube seized the opportunity to evacuate a few individuals: his orderly and his clerk, his Chief of Staff Colonel Hans-Jürgen Dingler, and Rudolf Sieckenius.

Reflecting on the events, one of Sieckenius' subordinate battalion commanders, Bernd Freytag von Loringhoven, remarked, "Sometimes he was inevitably nervous and gruff, but at heart, he was a caring superior.

The 16th Panzer Division performed adequately in Italy for six months between June and November 1943, seeing action at Salerno, Naples and Termoli before being sent back to the Eastern Front.

According to Major Udo von Alvensleben, the divisional Intelligence Officer, it was their commanding general Traugott Herr who made Sieckenius a scapegoat for Salerno and Termoli.

On 13 September 1943, for no good reason, 10th Army commander Heinrich von Vietinghoff came to believe that the invaders were about to re-embark and sent this misinformation to Berlin, and General Herr promptly ordered the 16th Panzer Division to launch a counterattack.

[16] The defeat at Termoli drew direct attention from Hitler, causing many panicked generals to hastily shift the blame onto Sieckenius, despite his relatively minor role in the failure.

On 9 August 1944, the tenth day of almost non-stop intense fighting, Schörner, known for his brutality and harsh disciplinary measures against his own troops, showed up at the 263rd Division HQ.

In the last weeks of the war, the Division HQ was situated on an estate near Frankfurt an der Oder, presumably Gut Bomsdorf, owned by the von Kunow family.

[23] On April 29, 1945, when Army Commander General Theodor Busse had already fled with heavy Panzers to save his own skin, Sieckenius stayed with his men and organized the remaining armoured cars and troops for a break out.

They managed to break through Halbe and advance into the forests south of Lake Teupitz, where they encountered an ambush by Soviet tanks and anti-tank guns.

One of his officers recounted the events in a post-war letter:[24] Towards the evening of a Sunday (29 April 1945 was Sunday), I can no longer recall the exact date, General Sikenius(sic) and General von Roden organized all the units in and around Halbe to a breakout attempt...After marching for about two hours, the spearhead was attacked by some Russian tanks which fiercely resisted.

In the midst of fighting, General Sikenius left his SPW and personally attack the enemy tank with a Panzerfaust in the forest.He then suffered a severe abdominal wound and, as a staff officer who had remained with him witnessed, chose to take his own life.