It doesn't get more interesting than this. Eastern Europe is the broad region stretching from the Baltic Republics through the European part of Russia, Belarus, and the Ukraine. These regions are crossed by navigable rivers and the Ukraine is covered by open plains favorable to nomadic peoples from farther east. As a result, nations have come and gone in profusion, intermingling freely without well established boundaries. Visitors tend to come from three directions.
Second - Third Century Germanic migrations: During the first century, several Germanic nations migrated from what is now southern Sweden to what is now Poland. One of these the Goths was settled in the Ukraine by the third century. If your ancestors were Christians in the Ukraine in 1000 CE, then their Gothic ancestors might also have lived in Poland and Sweden, in 1 CE. (Note: A Flemish traveler in the Crimea in the 16th century was surprised to find people speaking a Germanic language. It was a last remnant of Gothic.)
Fourth Century Hunnish migrations: The first historical invasion from Central Asia occurred during the fourth century when the Huns, a Mongolian people, invaded the Ukraine. (This event split the Goths into two nations, the East Goths (Ostrogoths) who submitted to Hunnish rule, and the West Goth (Visigoths) who fled into the Roman Empire.) The Huns eventually assimilated, but not before having left their genetic mark. If your ancestors were Christians in the Ukraine in 500 CE, they likely had Hunnish ancestors in Mongolia in CE 1.
Fifth Century Slavic migrations: During the fifth century, the Slavs appear in history, having expanded throughout Eastern and Central Europe from their homeland somewhere in the Ukraine and Southern Russia.
Seventh Century: Nomad kingdoms. Starting in the fourth century, semi-nomadic nations from Western Siberia, including the Bulgars, Magyars, and Khazars (maybe) had migrated into Southern Russia and the Ukraine. By the seventh century, the Bulgars had established a kingdom encompassing much of the region. Also at this time, the Turks, a Mongolian people, spread into Central Asia, where they fragmented into a bewildering variety of Turkic nations, each with its own interesting history. As they went, they intermarried with locals, resulting in today's wide range of physical variation among Turkic peoples. Various Turkic nations settled in the Ukraine including:
Starting in the 9th century and lasting into the 11th - the "Viking age", Scandinavians from Sweden began to trade, raid, then settle along the rivers of Russia and the Ukraine. These settlers ("Rus" in Old Norse) founded the oldest cities in the region and became the aristocrats of the new composite nation of Russia (a composite of Swedes, Finns, Baltic nations, and Slavs, but speaking a Slavic language). If your ancestors lived in Russia or the Ukraine in 1000 CE, it's safe to assume that they had ancestors in Sweden as well in 500 CE.
13th Century Mongol Invasions: In the early 13th Century, Genghis Khan united the Mongols and led them on history's most spectacular career of conquest. European Russia submitted to the Mongols and remained their subjects for over two centuries. Mongolia was never a populous nation, and governing the largest empire in history stretched them very thin, however they maintained an excellent communications system and used it to move talented people wherever they were needed. Thus, genes from anywhere in their empire (especially its core in Mongolia and central Asia) could have arrived in your Russian and Ukraine ancestors. If your ancestors lived in Russia or the Ukraine in 1490 CE, they could have had ancestors anywhere in the Mongol Empire in 1000 CE.
15th Century Muscovy: Before the arrival of the Mongols, Russia had been a collection of independent city-states. As Mongol power disintegrated during the 14th century, the power vacuum was filled by a minor upstart city - Moscow, which became the center of a new, united Russian Empire. From this point until CE 1918, Russia's borders expanded in all directions, but particularly into Siberia and Central Asia. Where Russian soldiers and administrators went, Russian genes got "planted." Thus, if your ancestors lived anywhere within the borders of the Russian Empire in CE 1900, it's likely that they had ancestors living in the heart of European Russia in CE 1490..
Sixteenth Century Ukraine - an imperial wrestling mat: During the early sixteenth century, the Empire of the Ottoman Turks (themselves and interesting ethnic mix) expanded to encompass the northern shores of the Black Sea and the Crimea. During the eighteenth century, the combined kingdoms of Poland and Lithuania annexed the northern and western portions of the region, settling Ashkenazi Jewish administrators to oversee their lands (the likely origin of recent Ukrainian Jews, Khazars notwithstanding.) Finally during the late eighteenth century Russia expanded toward the Black Sea, effectively annexing all but a few Ottoman toeholds by CE 1800. (The Crimean war of the 1850s was an effort by Western Europe to help the Ottomans resist the Russian steamroller.) If your ancestors lived in the southern Ukraine in 1800 CE, they could have had ancestors from any of these imperial powers in CE 1490..
Cossacks: Note, however, that southern Ukraine was largely a lawless land from the sixteenth to the eighteenth centuries, often "governed" by military fraternities known as Cossacks. (The word stems from the Turkish word for "adventurer" - no connection with Khazars.) Imagine a Mad-Max world in which biker-gangs were the only source of civic order and you'll have the idea of what it was like to live among them. (Check out their "diplomatic correspondence" with Ottoman Emperor Mehmet IV for a taste of life in Cossack-land.) Jewish communities settled in the Ukraine by Polish nobles during the seventeenth century tended to see the Cossacks' bad side. One good thing about the Cossacks, they despised the system of serfdom (slavery) practiced farther north in Russia and offered a safe haven to anyone escaping. Thus, if your ancestors were Christians living in the Ukraine in CE 1800, it is quite likely that they had ancestors working the fields in the Russian heartland in CE 1490.