he had subjugated the Poliane, Severiane, Vyatichi, and Radimichs, forbidding them to pay further tribute to the Khazars. Oleg continued to develop and expand a network of Rus' forts in Slav lands, begun by Rurik in the north. The new Kievan state prospered due to its abundant supply of furs, beeswax, honey and slaves for export, and because it controlled three main trade routes of Eastern Europe. In the north, Novgorod served as a commercial link between the Baltic Sea and the Volga trade route to the lands of the Volga Bulgars, the Khazars, and across the Caspian Sea as far as Baghdad, providing access to markets and products from Central Asia and the Middle East. Trade from the Baltic also moved south on a network of rivers and short portages along the Dnieper known as the "route from the Varangians to the Greeks," continuing to the Black Sea and on to Constantinople. Kiev was a central outpost along the Dnieper route and a hub with the east–west overland trade route between the Khazars and the Germanic lands of Central Europe. and may have been a staging post for Radhanite Jewish traders between Western Europe, Itil and China. These commercial connections enriched Rus' merchants and princes, funding military forces and the construction of churches, palaces, fortifications, and further towns. Demand for luxury goods fostered production of expensive jewelry and religious wares, allowing their export, and an advanced credit and money-lending system may have also been in place. Early foreign relations Volatile steppe politics The rapid expansion of the Rus' to the south led to conflict and volatile relationships with the Khazars and other neighbors on the Pontic steppe. The Khazars dominated trade from the Volga-Don steppes to the eastern Crimea and the northern Caucasus during the 8th century during an era historians call the 'Pax Khazarica', trading and frequently allying with the Byzantine Empire against Persians and Arabs. In the late 8th century, the collapse of the Göktürk Khaganate led the Magyars and the Pechenegs, Ugrians and Turkic peoples from Central Asia, to migrate west into the steppe region, leading to military conflict, disruption of trade, and instability within the Khazar Khaganate. The Rus' and Slavs had earlier allied with the Khazars against Arab raids on the Caucasus, but they increasingly worked against them to secure control of the trade routes. The Byzantine Empire was able to take advantage of