The relationship between Poles and Lithuanians has been long and complex. Their countries were united during the era of the Polish–Lithuanian Commonwealth, but both nations lost their independence after the Commonwealth was partitioned in the late 18th century. Both nations regained their independence in the wake of World War I, but hostilities over the ownership of Vilnius and the surrounding region broke out in 1920. The disputes became politically moot after the Soviet Union exercised its authority over both countries during and immediately after World War II. Some tensions over the Vilnius Region resurfaced after Lithuania regained its independence in 1990, but have since remained at manageable levels. Poland was highly supportive of Lithuanian independence and became one of the first countries to recognise independent Lithuania, despite apprehensions over Lithuania's treatment of its Polish minority.