In 229 BC, Croatia's native Illyrians lost their land to the Roman empire - in Ad 285, Emperor Diocletian built the palace fortress in Split, now the greatest Roman ruin in eastern Europe. The Western Roman empire collapsed in the 5th century, and around 625, Slavic tribes migrated to Croatia from present-day Poland. The Croatian tribe moved into what is now Croatia, occupying the former Roman provinces of Dalmatian Croatia and Pannonian Croatia to the northeast. The two provinces were united in 925 into a single kingdom which prospered into the 12th century.
In 1242 a Tatar invasion devastated Croatia. In the 16th century, as the Turks threatened to take over the Balkans, northern Croatia turned to the Habsburgs of Austria for protection, remaining under their influence until 1918. Meanwhile, the Dalmatian coast was taken by Venice in the early 15th century and held until the end of the 17th century, when it was taken by Napoleonic France and made part of the Illyrian provinces (along with Istria and Slovenia).
A revival of Croatian cultural and political life began in 1835 - the serfs were liberated, and northern Croatia came under the rule of Hungary, which granted it a degree of internal autonomy. When the Austro-Hungarian empire was defeated in WWI, Croatia became part of the Kingdom of Serbs, Croats & Slovenes, mercifully shortened to Yugoslavia in 1929. Croatian nationalists were angered that Belgrade was made capital of the union and, with the help of Macedonian nationalists, organised the assassination of King Alexander in 1934 in protest.
In 1941 Germany invaded Yugoslavia and set up a fascist puppet government (the Ustashe) in Croatia. The Ustashe tried to expel all Serbs from Croatia, and when this didn't work they set the pattern for ethnic cleansing by murdering around 350,000 ethnic Serbs, Jews and Roma. Not all Croats agreed with this policy, and many joined with the communist partisans to overthrow the Ustashe. By the time the war ended, about a million people had died in Croatia and Bosnia-Hercegovina.
Postwar Croatia was granted republic status within the Yugoslav Federation, governed by the communist Marshal Tito. As Croatia outstripped the southern republics economically, it demanded greater autonomy, bringing a series of purges down on the heads of its residents during the 1970s. When Tito died in 1980, a farcical political system was instituted which resulted in the presidency rotating annually between the republics, and Croatia's economy ground to a halt.
In the late 1980s, severe repression of the Albanian majority in Serbia's Kosovo province sparked fears that Serbia was trying to impose its rule over the rest of the Federation. As communist governments fell throughout eastern Europe, Croats began agitating for autonomy and an end to communism. In 1990 Franjo Tudjman's Croatian Democratic Union won elections. A new constitution was instituted which changed the status of Serbs in Croatia to a 'national minority' rather than a 'constituent nation'. Serbian rights were not guaranteed by the new constitution, and many Serbs lost their government jobs.
In June 1991 Croatia declared its independence from the Federation, and the Serbian enclave of Krajina declared its independence from Croatia. Heavy fighting broke out throughout the country, and the Yugoslav People's Army, dominated by Serb communists, intervened in support of the Serbs. When things looked hairy, Croatia agreed to freeze its independence declaration for three months. Nonetheless, fighting continued, and a quarter of Croatia fell to Serb militias and the federal army. In October 1991 the federal army moved against Dubrovnik and bombed the presidential palace in Zagreb, sparking EU sanctions against Serbia. In November Vukovar fell to the Serbs after a three-month siege. In six months, 10,000 people had died, hundreds of thousands had fled, and tens of thousands of homes had been destroyed.
After a series of unsuccessful cease-fires, the United Nations (UN) deployed a protection force in Serbian-held Croatia in December 1991. The federal army withdrew from Croatia and in May 1992 Croatia was admitted to the UN, after amending its constitution to protect minority groups and human rights. In Krajina, Serb paramilitary groups retained the upper hand and, in January 1993, Croatia launched an attack on the area. Krajina responded by declaring itself a republic and reducing its Croat population by nearly 98%. In March 1994, Krajina signed a cease-fire but, in May 1995, violence again exploded. Krajina lost the support of Belgrade, Croatian forces flooded the area, and 150,000 Serbs fled, many from towns where their ancestors had lived for centuries.
The Dayton agreement of December 1995 eventually brought a sense of stability to the country, allowing the government to attempt to deal with unemployed ex-soldiers, housing for displaced Croats and a severely damaged infrastructure.
President Franjo Tudjman died in December 1999, and in January 2000 his Croatian Democratic Union, which had ruled since 1990, was convincingly ousted by the center-left opposition coalition. The charismatic yet earthy Stipe Mesic was elected president. The new government has promised to improve international relations, freedom of the press, the state of the economy and to address the country's atrocious human-rights record.