Bulgaria was the last state to join the central powers in the first world war and the first to leave them. It was also the only defeated state to retain the political system with which it went to war, namely that devised at Tûrnovo in 1879. But Bulgarian politics in the inter-war years, at least until 1934, was to display a turbulence and a violence much in contrast with constitutional continuity.
In late September 1918 the allied forces in northern Greece, the long-derided ‘Gardeners of Salonika’, lunged into the Bulgarian army in Macedonia and drove it back into Bulgaria. By 29 September the demoralised Bulgarian régime had both concluded an armistice and released a number of political detainees, including the powerful leader of the Bulgarian Agrarian National Union (BANU), Aleksandûr Stamboliiski. This had been done in the hope that the agrarian leader would be able to contain growing unrest in the army but this he proved unable, and perhaps unwilling, to do. A rebellion centred upon the town of Radomir to the west of Sofia threatened to develop into a nation-wide revolution. In the event social collapse was prevented by a combination of German units moved in from the Ukraine, a number of die-hard Macedonians under general Aleksandûr Protogerov, the mass desertions which even the radicalised army experienced, and the refusal of the extreme left to cooperate with BANU. The Radomir rebellion fizzled out in a bungled attempt to take Sofia.
It had been widely assumed that the allied armies which were then advancing into the country would not welcome a Bulgarian variant of bolshevism but noone objected to the one major and immediate political demand made by the allies: the removal of King Ferdinand. He left Bulgaria immediately, to be succeeded by his son, Boris III.
The king was as yet too young and inexperienced to play a key role in Bulgarian politics. After the disasters of 1913 and 1918 the army was discredited, as were the old parties of the sûbranie (parliament). The factions contending for power were therefore the agrarians, the socialists, and the Macedonians. The agrarians enjoyed extensive popular support and had the advantages of an