The Principality of Liechtenstein was established within the Holy Roman Empire in 1719. Occupied by both French and Russian troops during the Napoleonic Wars, it became a sovereign state in 1806 and joined the German Confederation in 1815. Liechtenstein became fully independent in 1866 when the Confederation dissolved. Until the end of World War I, it was closely tied to Austria, but the economic devastation caused by that conflict forced Liechtenstein to enter into a customs and monetary union with Switzerland. Since World War II (in which Liechtenstein remained neutral), the country's low taxes have spurred outstanding economic growth. In 2000, shortcomings in banking regulatory oversight resulted in concerns about the use of financial institutions for money laundering. However, Liechtenstein implemented anti-money laundering legislation and a Mutual Legal Assistance Treaty with the US that went into effect in 2003.