The Greek flag was officially adopted in 1978, though an earlier version with a diagonal cross was used since 1822 following Greece's independence from the Ottoman Empire. The nine stripes represent a Greek phrase meaning "Freedom or Death" and the cross represents the Greek Orthodox Church. Blue symbolizes the sea's importance to Greece and white represents ocean waves and purity. Greece has a Mediterranean climate along the coasts and a temperate climate in central and northern regions. It has few natural resources besides lignite coal and deposits of oil and gas offshore in the Aegean Sea. Germany and Italy are Greece's main EU trading partners.