In the 2000s, the government began leaning towards NATO, and a deeper cooperation with the alliance was set by the NATO-Ukraine Action Plan signed in 2002.It was later agreed that the question of joining NATO should be answered by a national referendum at some point in the future.Northern migrations, reaching almost to the Ilmen Lakes, led to the emergence of the Ilmen Slavs, Krivichs, and Radimichs, the groups ancestral to the Russians.After an Avar raid in 602 and the collapse of the Antes Union, most of these peoples survived as separate tribes until the beginning of the second millennium.Beginning in the sixth century BC, colonies of Ancient Greece, Ancient Rome and the Byzantine Empire, such as Tyras, Olbia and Chersonesus, were founded on the northeastern shore of the Black Sea.These colonies thrived well into the 6th century AD.A Cossack republic emerged and prospered during the 17th and 18th centuries, but its territory was eventually split between Poland and the Russian Empire, and later merged fully into Russia.During the 20th century three periods of independence occurred.
Kievan Rus' included the central, western and northern part of modern Ukraine, Belarus, far eastern strip of Poland and the western part of present-day Russia.
Excluding Crimea, Ukraine has a population of about 42.5 million, making it the 32nd most populous country in the world.
The territory of modern Ukraine has been inhabited since 32,000 BC.
The third period of independence began in 1991, when Ukraine gained its independence from the Soviet Union in the aftermath of its dissolution at the end of the Cold War.
Ukraine has maintained its independence as a sovereign state ever since.