In January 1944 Adolf Hitler ordered Reichführer SS Heinrich Himmler to raise a Waffen SS division from a cadre of SA reservists. It's a difficult order for Himmler to swallow, as the SS was once the neglected stepchild of the SA - until the SS assassinated the SA leadership under Hitler's orders in the 1934 "Night of the Long Knives." But the ever-dutiful Himmler scrapes together the Horst Wessel division, not from SA reservists but from 1 st SS Brigade (motorized), 6 th SS Gebirgs Division “Nord” and Hungarian Volksdeutsche.  

From May 1941 to December 1943 the 1 st SS Brigade served as a part of the Kommandostab Reichsführer SS a fought for almost 3 years with Army Group "Mitte" in central Russia in antipartisan operations, including support for the Einsatzgruppen.

1 st SS Brigade upgraded to become the 18 th SS Freiwilligen Panzergrenadier Division “Horst Wessel”. Unit transferred to Zagreb area. In February 1944 the Division was reinforced by additional personnel inclusive of Hungarian Volksdeutsche and Assault Gun Battalion from 6 th SS Gebirgs Division “Nord”.

In March 1944 Division participated in Operation “Margarethe” which was German military occupation of Hungary , as a part of Battle Group Zwade. From July to August 1944 the Division was trained in Hungary and after the training it was sent to Ukraine as a part of Battle Group Schäfer. At the territory of Ukraine and later in Poland took part in heavy combats against Red Army near Lvov and Sanok supported by additional elements of 1 st SS Sturmbrigade „Charlemagne“.  

In September 1944 division was again trained in Hungary and was involved in the antipartisan operations. G. Berger, head of the SSFHA, appointed HSSPF for Slovakia and 1,800 divisional troops were sent to Slovakia to quell Slovak National Uprising. In October 1944 the Division participated in Grand Offensive against Slovak National Uprising and in November 1944 the Division was moved to Slovakia to secure the situation there after Slovak National Uprising. After this period of time the Division participated in heavy combat near Budapest until December 1944 where was rejoined by Battle Group Schäfer. On 24 th December 1944 Budapest surrounded.