On 11 November 1918, when the peace was signed at Compiègne, the Austrian-Hungarian Emperor Karl issued a proclamation in which he recognized the Austrian people's right to determine the form of the state and relinquished every participation in the administration of the State 1 
He also released his officials from their oath of loyalty to him. By effect he did not really abdicate, but he made himself available when necessary. He hoped that the Austrian people would one day call him and the Monarchy back. 2
That same evening the Imperial Family left Schönbrunn Palace and moved to Castle Eckartsau, east of Vienna. When leaving the palace some official called him "Herr Habsburg", without any formal honors. The Monarchy was over. 3
On 13 November 1918 he received a visit of the Hungarian magnates at Eckartsau. This was the occasion to issue a similar proclamation for Hungary, the so called Eckartsau Proclamation. However the new leaders of Austria and Hungary did not really care anymore. 4
On 12 November 1919 the independent Republic of German-Austria was proclaimed, followed by the proclamation of the Hungarian Democratic Republic on 16 November. It became clear that the presence of a Emperor in a republic became something odd. 5
The new Austrian Government wanted a real abdication of Karl, who persisted on his terms. The situation stay restless until 23–24 March 1919, when Karl left for Switzerland, escorted by the commander of the small British guard detachment at Eckartsau, Lt. Col. Strutt (photo). 6
As the Train left Austria on 24 March, Karl issued another proclamation in which he confirmed his claim of sovereignty, declaring that whatever the assembly of German Austria has resolved since 11 November was null and void for him and his House. 7
This meant a declaration of war to the new Austrian leaders. In effect the Austrian Parliament decided to pass the Habsburg Law on 3 April 1919, which permanently barred Charles from returning to Austria. 8
Other Habsburgs were also banished from Austrian territory unless they renounced all intentions of reclaiming the throne and accepted the status of ordinary citizens. Another law, passed on the same day, abolished all nobility in Austria. 9
Parts of the Habsburg law were abolished in the 1990s as condition for Austria to join the EU, especially the rule that the family Habsburg could not enter Austria. The son of Karl, Otto von Habsburg had to wrestle with the law to finally gain entrance to Austria in 1960s. 10
