Solidarity (, pronounced ; full name: Independent Self-governing Trade Union "Solidarity" – Niezalezny Samorzadny Zwiazek Zawodowy „Solidarnosc” ) is a Polish trade union that was founded on 17 September 1980 at the Gdansk Shipyard under the leadership of Lech Walesa. It was the first trade union in a Warsaw Pact country that was not controlled by a communist party. Its membership reached 9.5 million members before its September 1981 Congress (when it reached 10 million), which constituted one third of the total working-age population of Poland.