The history of Bulgaria can be traced from the first settlements on the lands of modern Bulgaria to its formation as a nation-state, and includes the history of the Bulgarian people and their origin. The earliest evidence of hominid occupation discovered in what is today Bulgaria date from at least 1.4 million years ago. Around 5000 BC, a sophisticated civilization already existed which produced some of the first pottery, jewellery and golden artifacts in the world. After 3000 BC, the Thracians appeared on the Balkan Peninsula. In the late 6th century BC, parts of what is nowadays Bulgaria, in particular the eastern region of the country, came under the Persian Achaemenid Empire. In the 470s BC, the Thracians formed the powerful Odrysian Kingdom which lasted until 46 BC, when it was finally conquered by the Roman Empire. During the centuries, some Thracian tribes fell under ancient Macedonian and Hellenistic, and also Celtic domination. This mixture of ancient peoples was assimilated by the Slavs, who permanently settled on the peninsula after 500 AD. Meanwhile, in 632 the Bulgars formed an independent state north of the Black sea that became known as Great Bulgaria under the leadership of Kubrat. Pressure from the Khazars led to the gradual disintegration of Great Bulgaria in the second half of the 7th century. One of Kubrat's successors, Asparuh, leading some of the Bulgar tribes settled in the area around the Danube delta, and subsequently conquered Scythia Minor and Moesia Inferior from the Byzantine Empire, expanding his new kingdom further into the Balkan peninsula. The crucial Battle of Ongal in 680, the peace treaty with Byzantium in 681, and the establishment of a permanent Bulgarian capital at Pliska south of the Danube mark the beginning of the First Bulgarian Empire. The new state brought together local Byzantine population and migrant population as Early Slavs under Bulgar rule, and a slow process of mutual assimilation began. In the following centuries Bulgaria established itself as a powerful empire, dominating the Balkans through its aggressive military traditions, which led to development of a distinct ethnic identity. Its ethnically and culturally diverse people united under a common religion, language and alphabet which formed and preserved the Bulgarian national consciousness despite foreign invasions and influences. In the 11th century, the First Bulgarian Empire collapsed under multiple Rus' and Byzantine attacks and wars, and was conquered and became part of the Byzantine Empire until 1185. Then, a major uprising led by two brothers, Asen and Peter of the Asen dynasty, restored the Bulgarian state to form the Second Bulgarian Empire. After reaching its apogee in the 1230s, Bulgaria started to decline due to a number of factors, most notably its geographic position which rendered it vulnerable to simultaneous attacks and invasions from many sides. A peasant rebellion, one of the few successful such in history, established the swineherd Ivaylo as a Tsar. His short reign was essential in recovering—at least partially—the integrity of the Bulgarian state. A relatively thriving period followed after 1300, but ended in 1371, when factional divisions caused Bulgaria to split into three small Tsardoms. By 1396, they were subjugated by the Ottoman Empire. The Turks eliminated the Bulgarian system of nobility and ruling clergy, and Bulgaria remained an integral Ottoman Empire territory for the next 500 years. With the decline of the Ottoman Empire after 1700, signs of revival started to emerge. The Bulgarian nobility had vanished, leaving an egalitarian peasant society with a small but growing urban middle class. By the 19th century, the Bulgarian National Revival became a key component of the struggle for independence, which would culminate in the failed April uprising in 1876, which prompted the Russo-Turkish War of 1877–78 and the subsequent Liberation of Bulgaria. The initial Treaty of San Stefano was rejected by the Great Powers, and the following Treaty of Berlin limited Bulgaria's territories to Moesia and the region of Sofia. This left many ethnic Bulgarians out of the borders of the new state, which defined Bulgaria's militaristic approach to regional affairs and its allegiance to Germany in both World Wars. After World War II, Bulgaria became a Communist state, and the General Secretary of the Bulgarian Communist Party, Todor Zhivkov, served for a period of 35 years, where there was relatively rapid economic growth. The Communist system collapsed in the 1980s, and several problems in the 1990s decreased the economic development of Bulgaria's agricultural and other industries. A period of relative stabilization began with the election of Simeon Saxe-Coburg-Gotha as prime minister in 2001. Bulgaria joined NATO in 2004 and the European Union in 2007. Source: Wikipedia (en)