| c 2500 BC | Thracian civilisation established in south east of Balkan peninsula. | |
| c 600 BC | Thrace colonised by Greeks. | |
| c 100 BC | Thrace becomes part of Roman Empire. | |
| 15 AD | Moesia (northern Bulgaria) becomes part of Roman Empire. | |
| c 500 AD | Slavic tribes begin to settle Thrace and Moesia (modern Bulgaria). | |
| c 600 AD | Nomadic Asiatic Bulgars invade and become ruling elite. They later absorb Slavic language and culture. | |
| 680 AD | First Bulgarian Empire under Khan Asparuhk stablished. | |
| 864 | Christianity introduced. | |
| 893 | Empire reaches its zenith under Tsar Simeon – controlling Macedonia & Serbia. | |
| 969 | Russians invade Bulgaria. | |
| 976 | Byzantine Empire drives Russians from Bulgaria. | |
| 1018 | Bulgaria becomes part of Byzantine Empire. | |
| 1185 | Successful revolt against Byzantine rulers. Second Bulgarian Empire established. | |
| 1330 | Bulgaria defeated by Serbs – made a tributary. | |
| 1389 | Ottoman Turks invade. | |
| 1396 | Bulgaria becomes part of Ottoman Empire. | |
| 1850s | Revolutionary movement for national independence grows. | |
| 1876 | Revolt against Ottoman rule – 15,000 killed by Turks in reprisals. | |
| 1877 | Russia invades Balkans to protect Bulgarian Christians. Start of Russo-Turkish War. | |
| 1878 | Russo-Turkish War ends after several Turkish defeats. Russia occupies large parts of Ottoman territory. | |
| 3 March 1878 | Treaty of San Stefano – Turks agree to independence for Romania, Serbia and Montenegro, autonomy for Bulgaria and to cede territory to Russia. | |
| 13 July 1878 | Treaty of Berlin – European powers re-write Treaty of San Stefano to reduce Russian gains. | |
| 1878 | Autonomous principalities of Bulgaria and Eastern Rumelia established within the Ottoman Empire. | |
| 6 September 1885 | Eastern Rumelia (South Bulgaria) incorporated into the autonomous Bulgarian principality. | |
| 13 November 1885 | Serbo-Bulgarian War begins when Serbia tries to oppose annexation of Rumelia. War ends 13 March 1886 after Serbia defeated. | |
| 5 October 1908 | Independent Kingdom of Bulgaria established. | |
| March 1912 | Alliance beween Serbia and Bulgaria agreed. | |
| June 1912 | Alliance between Greece and Bulgaria agreed. | |
| 8 October 1912 | Montenegro declares war on Ottoman Empire – starting First Balkan War. | |
| 18 October 1912 | Serbia, Bulgaria and Greece join the First Balkan War. [5 Oct, Julian calendar] | |
| 16 December 1912 | Armistice in First Balkan War agreed by Ottoman Empire. [3 Dec, Julian calendar] | |
| 3 February 1913 | First Balkan War resumes after change of government in the Ottoman Empire. [21 Jan, Julian calendar] | |
| 26 March 1913 | Ottoman fortress of Adrianople falls to Bulgarian forces. [13 Mar, Julian calendar] | |
| 19 April 1913 | Armistice agreed following victory over the Ottoman Empire. | |
| 30 May 1913 | Peace Treaty signed following First Balkan War. | |
| 1 July 1913 | Start of Second Balkan War – led by the country allies from the First Balkan War (Serbia, Greece, Bulgaria) with the aim of ruling Macedonia. [16 June, Julian calendar] | |
| 30 July 1913 | Armistice ends Second Balkan War. | |
| 10 August 1913 | Peace treaty signed in Bucharest – the territory of Macedonia was partitioned into three parts among Bulgaria, Serbia and Greece. | |
| 24 August 1915 | Bulgaria signs a military pact with Germany and Austro-Hungary. | |
| 14 October 1915 | Bulgaria declares war on Serbia, entering the First World War on the side of Germany. [1 Oct, Julian calendar] | |
| 29 September 1918 | Bulgaria surrenders to the Allies. | |
| late 1918 | Peasant led ‘Agrarian’ government takes control. | |
| 27 November 1919 | Bulgaria signs humiliating peace treaty in Neuilly. | |
| June 1923 | Bloody military coup deposes Agrarian government. | |
| 1934 | Government of ‘national regeneration’ installed by military coup. | |
| 1935 | Czar Boris establishes quasi-fascist royal dictatorship. | |
| 15 September 1939 | Bulgaria declares neutrality in World War Two. | |
| 7 September 1940 | Craiova Agreement – Romania cedes South Dobrudja to Bulgaria. | |
| 21 September 1940 | Bulgarian Army enters South Dobrudja. | |
| 1 March 1941 | Bulgaria signs Axis Tripartite Pact. | |
| 6 April 1941 | German forces invade Greece and Yugoslavia from Bulgarian bases. | |
| 24 April 1941 | Bulgaria declares war on Greece and Yugoslavia. | |
| late April 1941 | Bulgarian military forces occupy Macedonia and Aegean Thrace. | |
| 13 December 1941 | Bulgaria declares war on Britain and the USA. | |
| 26 August 1944 | Bulgaria declares itself neutral in WW2 – not recognised by Allies. | |
| 30 August 1944 | German troops withdraw from Bulgaria. | |
| 5 September 1944 | USSR declares war on Bulgaria. | |
| 6 September 1944 | Bulgaria declares war on Germany. | |
| 8 September 1944 | Soviet troops enter Bulgaria unopposed. | |
| 9 September 1944 | Armistice signed with USSR. | |
| 9 October 1944 | Anti-German offensive in Yugoslavia launched. | |
| 28 October 1944 | Armistice with Britain, USA and USSR signed. | |
| 2 December 1944 | Anti-German advance into Southern Serbia and Macedonia concluded. | |
| 1945 | Control of Macedonia transferred to Yugoslavia, of Thrace to Greece and of South Dobruja to Romania | |
| October 1946 | Communists ‘win’ government elections and take control. | |
| 15 September 1947 | Formal peace treaty with USSR signed | |
| 1947 | People’s Republic of Bulgaria established | |
| 10 November 1989 | Communist Party leadership replaced by pro-democracy supporters. | |
| February 1991 | First non-Communist government elected in Bulgaria. | |
| 14 February 1994 | Bulgaria joins the NATO Partnership for Peace programme. | |
| mid 2001 | Supporters of the former King Simeon of Bulgaria win government elections | |
| November 2002 | Bulgaria invited to join NATO. | |
| 2 April 2004 | Bulgaria joins NATO |
Note: Bulgaria switched to the Gregorian calendar when 31 March 1916 was followed by 14 April 1916.