They are all Slavs, descended from people of Asian origin who settled the region in the seventh century - Yugoslavia means the land of the south Slavs. But their histories since then have been very different. The Serbs, mostly Orthodox Christians, are a warrior nation who once controlled a large empire in the Balkans before falling under the rule of the Ottoman Turkish empire at the end of the Middle Ages. In the early 19th century they rose against the Turks and eventually liberated Serbia, creating, once again, an independent kingdom. This history of struggle and liberation has left a lasting mark on the Serbian self-image.
The experience of the Croats has been totally different. These Slavs of the north and west fell under Western influence, became Roman Catholics and were ruled, in the main, by the Austro-Hungarian empire of the Habsburgs. They have given a fashion and a word to the West: 'cravat' is a corruption of the word Croat.
For centuries, then, Serb and Croat were divided by a military frontier which was more than a mere boundary between countries - it was the line between East and West. The two nationalities share a language, Serbo-Croat, but their dialects have evolved differently and, when they speak, they can usually tell each other apart. The principal symbolic division between Serb and Croat is in their writing, for the Serbs use the Cyrillic script in which Russian is written, while the Croats use our Roman alphabet.
The Muslims are descended from Slavs living in central Yugoslavia who, in the Middle Ages, embraced the Bogomil heresy, a kind of Western Zoroastrianism, and were persecuted as a result. They welcomed the Turkish conquest in the 15th century as a release from this, and converted to Islam.
Why do they hate each other so much?
The Second World War has a lot to do with it. Serbs and Croats have traditionally suspected each other of a will to dominate, and those suspicions have often been encouraged by the bigger powers involved in the region. Between the wars, when Yugoslavia was a united kingdom, Croats came to resent what they saw as Serbian rule - the king was Serb, as was the army leadership, and the capital was Belgrade, in Serbia. When the Germans overran the country in 1941, many Croats took revenge. A Fascist puppet state of Croatia was set up, covering Bosnia as well, and brutal repression, even extermination, of Serbs began. There followed a civil war of appalling cruelty, in which the Germans were sometimes mere bystanders, and in which well over a million Yugoslavs died. Almost every town and village harbours grievances arising from wartime atrocities.
How did Tito manage to keep the peace?
Tito, son of a Croatian father and Slovene mother, was resented by both Serbs and Croats. He tried to reduce the influence of both by increasing the status of other nationalities - Macedonians, Slovenes and, to a lesser extent, Muslims. He angered Serbs by making two provinces within Serbia autonomous. Croats, for their part, remembered the wartime persecution of the Catholics by Tito's partisans. Despite these tensions, the Yugoslavs were held together by the harshness of the Communist system, which forbade all unofficial expressions of nationalism. Also, after Tito's break with Stalin in 1948, they felt they had to stick together in case the Soviet Union tried to establish control of the country.
What is Bosnia- Herzegovina?
Serbia is mainly Serbian and Croatia mainly Croat. Bosnia-Herzegovina, the land in between, is an ethnic jigsaw further complicated by the presence of the Muslims. Bosnia is the northern part, named after a river once called the Bosanius, while Herzegovina, previously the land of Hum, owes its name to the German word Herzog, or duke. The two regions, which together we will simply call Bosnia, were under Ottoman control for centuries until rebellions in the 1870s gave the Austro-Hungarians the opportunity to take over.
Bosnia's history, like its demography, is thus more muddled than those of its neighbours, and consequently the people have a less distinct sense of common identity. Serbs continued to identify with Serbia and Croats with Croatia, while Muslims tended to fear both sides. To that extent the notion that Bosnia is a nation in its own right is false.
After the Second World War Tito made Bosnia a republic on an equal footing with Serbia and Croatia, and the Bosnian people made a valiant effort to unite. At least until the present fighting, Muslims made up 44 per cent of the population, Serbs 32 per cent and Croats 17 per cent. They lived together fairly amicably. Even now, Bosnians often insist that they do not hate their neighbours.
What sort of government does Bosnia have?
It is a non-Communist one, democratically elected, but which now controls very little territory. Bosnia held its first multi- party elections in November 1990, and a Muslim-Serb-Croat coalition was formed under a Muslim president, Alija Izetbegovic. Last year, as Slovenia, Croatia and Macedonia successively voted for, and declared, independence, and serious fighting broke out in Croatia, Mr Izetbegovic desperately tried to keep his coalition together and prevent Bosnia from becoming embroiled. As tensions mounted, however, the Serbs withdrew from his government.
How did the war there start?
While Serbs and Croats fought in Croatia last year and the Yugoslav federation collapsed, leaders of the three main communities in Bosnia formed different views of the sort of independence they wanted. Serbs, fearing Muslim-Croat domination, wanted a link with Serbia, which the others believed would simply mean being swallowed in a 'Greater Serbia'. All three armed themselves to the teeth, the Serbs having the advantage that Yugoslav regular army garrisons in Bosnia were Serb-led. Last March, after pressure from the European Community, a referendum was held on independence. The Serbs boycotted the ballot, while most Muslims and Croats voted in favour. This meant 65 per cent of the electorate voted for independence, but without any ethnic consensus. Fighting broke out immediately.
What is the balance of forces?
It is estimated there are between 60,000 and 70,000 Bosnian Serbs under arms, with about 500 artillery pieces and heavy mortars and up to 300 tanks in Bosnia. Many of them belonged to a territorial force, Teritorijalna Odbrana, which was organised in small groups across Communist Yugoslavia. They have received support from the former Yugoslav army, which is sophisticated and well-armed. An important factor is that the arms industry of the former Yugoslavia was either based in Serbia or in Serbian-dominated parts of Bosnia and continues to supply the Serb forces.
The Bosnian Muslims and Croats together total about 100,000 and probably outnumber the Serbs who are fighting. But they are less well-armed, with few heavy weapons. They are dependent on imported arms and ammunition, and are thus in a sense penalised by the UN arms embargo in force against the region.
Has EC diplomacy made things worse?
The Community made mistakes from the start. Before the war, it failed to appreciate that Yugoslavia was going to break up and that the crucial question was how to guarantee human rights for ethnic minorities in the successor states. Instead, the EC warned Slovenia and Croatia against secession, providing an excuse for the Serbian-led Yugoslav army to strike at both.
The EC tried to make amends by setting up a commission of experts to recommend which Yugoslav republics deserved recognition as independent states. But when the experts said Croatia did not merit recognition because it had not provided proper guarantees for its Serbian minority, the EC recognised the republic anyway. When the experts said Macedonia did deserve recognition, Greece forced the other 11 EC states to reject the advice.
It is possible that the EC's peace-making efforts were doomed to failure because the participants were so incapable of reaching compromises. However, by identifying Serbia and President Slobodan Milosevic as the villains of the piece, the EC has missed the crucial point that the Serbs had a problem faced by no other south Slav nation: they had the largest number of their people living as minorities outside their home republic - 600,000 in Croatia and 1.4 million in Bosnia. Certainly, Mr Milosevic and other Serbian political and military leaders bear heavy responsibility for the war, and the Serbian treatment of Bosnia's Muslims has been atrocious. But to string up Mr Milosevic will do nothing to address the long-term problem facing Serbian minorities.
Which side is winning the war?
The Serbs are winning, mainly at the expense of the Muslims. Although both sides have some heavy weapons, the fighting is mainly guerrilla-style and very localised, so it is difficult to establish an absolutely clear picture. Still, it appears the Serbs have overrun about two-thirds of the republic and are holding the capital, Sarajevo, under tight siege. Two other Muslim towns, Gorazde and Bihac, are also under siege. Meanwhile the Croats have seized the opportunity to carve out an autonomous Croatian area in western Herzegovina.
What is meant by 'ethnic cleansing'?
'Ethnic cleansing' has worked like this: Serbian forces take control of a Muslim district. They then go from house to house demanding that every family signs an oath of loyalty and hands in its weapons. If they disobey the order, the men are rounded up and put in detention camps, where they are forced to sign away their property and pledge never to return home. Then they are deported to Croatia or simply flee abroad. Women and children generally leave separately, under harassment. If they sign the oath, they are still terrorised - their houses are bombed and burned, they are deprived of their jobs and so on. Often the Serbs make the Muslims sign a document stating that they want to live in Germany, Austria or wherever. The Serbs then contact United Nations people on the ground and say: we have these Muslims here who wish to go abroad, be prepared for them to come over. In this way, whole regions are cleared of Muslims. The Serbs insist the same is being done to their people by Croats and Muslims, but there is no evidence of such a systematic or formal policy.
What is happening to the refugees?
Between 1.5 million and 2 million people have been displaced in Yugoslavia. Many have remained in their home republics, drifting into areas they consider safe, or simply drifting. For some there are camps, food aid and other help. Some have found relatives to support them. Still more have fled across borders. Croatia alone is said to contain as many as 600,000 refugees - equivalent to one in eight of the population. It cannot hope to feed and accommodate them all; it is simply overwhelmed.
The outlook for these people is appalling. With winter coming - Balkan winters tend to be exceptionally harsh - the cold will become a serious problem, and with harvests and transport so badly disrupted there will be food shortages. Many more lives are likely to be lost.
This is one area where the international community, often reluctantly, has helped. Germany has taken more than 200,000 refugees, Austria and Hungary 50,000 and Sweden 44,000. Britain, however, has been slow to assist. The Government has announced that it is accepting 1,300, and last week it emerged that 36 asylum seekers had been deported.
Will the fighting spread to other countries?
It certainly could. Serbia's success in the field makes it the dominant power in the region, despite its diplomatic isolation and economic plight. This increases stresses on the southern Kosovo region, mainly made up of ethnic Albanians, which wants independence, and Macedonia, which has declared independence but is not internationally recognised. Macedonia's position is especially vulnerable because Serbia has a tacit agreement with Greece to keep it weak. Greece is deeply suspicious of Macedonia, which it fears has designs on its territory. Other countries could be drawn in if, for example, the Albanians of Kosovo rose up and Serbia clamped down on them, leading Albania and the Albanian minority in Macedonia to assist the Kosovars and to press for a united Greater Albania. Also, should the continued Western refusal to recognise Macedonia cause that republic to collapse in turmoil, Serbia, Greece and Bulgaria might feel tempted to intervene. The line-up then would be Serbia and Greece on one side, and Bulgaria, Macedonia and Turkey (traditionally anti-Greek) on the other.
Could international intervention repel the Serbs?
It would need a very large force. Estimates vary of the number of men required to pacify all of Bosnia and hold off the regular Serbian army as well. A conservative estimate is 200,000 to 300,000 troops, even bearing in mind the great technological superiority that an international force, particularly a Nato-backed one, would have, and the poor state of training and readiness of the former Yugoslav air force. In a full-scale war, Western forces would probably acquire command of the air very rapidly.
Didn't the Nazis subdue Yugoslavia easily?
The whole country fell to Nazi Germany in eight days, but that was after a brilliant campaign in which air attacks supported an invasion by about 300,000 men and 1,200 tanks. Even then, 5,000 Germans were killed or wounded. Holding the territory once it had been captured certainly pinned down a great many men, even though the Germans were often content merely to hold the capital and the main supply routes. In 1941-42 there were between 29 and 32 German and other Axis divisions in Yugoslavia: roughly 300,000 men. However, German policy towards the Yugoslavs was harsh and many felt they had little to lose by armed resistance. A UN force would be operating under different circumstances.
Is there anything else that could be done?
Another possibility for foreign military intervention is to attempt to secure a border or borders within Bosnia, marking out certain predominantly Muslim areas as 'safe havens'. This would probably require far fewer troops - about 100,000 perhaps - but politically it is very delicate, for freezing any de facto borders inside Bosnia is another way of recognising them, and this might mean effectively condoning the 'ethnic cleansing' that has taken place.
What is being considered now by the UN leadership is a range of lesser steps. These are: securing Sarajevo airport (which means keeping heavy weapons out of range), escorting aid convoys to besieged cities such as Sarajevo, and supervising the collection of heavy weapons. All this would probably require 20,000 to 25,000 troops. Helicopters would be useful for patrolling the convoy routes but these require a secure base nearby - Sarajevo airport - so the tasks are interlinked.
Is there any hope that Bosnia can be saved?
Very little. Bosnia is already partitioned de facto between Serbia and Croatia. Whether that will last depends mainly on whether the West decides that is unacceptable and takes action to reverse it. If Bosnia-Herzegovina is to be rebuilt as an independent state, then the essential requirement is respect for ethnic rights based on a form of government in which all nationalities are represented at all levels. This is most unlikely to happen with the current leaders in power, especially Radovan Karadzic, the Serb, and Mate Boban, the Croat. At a lower level, a whole new generation has been saturated in atrocity and grievance; it will be a long time before trust between the communities can be restored. The best that can be hoped for in Bosnia is that the war can be halted and 'ethnic cleansing' brought to an end. After that, it may be possible for the vast number of Muslim refugees to start returning to their homes.
Answers provided by Brian Cathcart; Christopher Bellamy, Defence Correspondent; Tony Barber, East Europe EditorReuse content