John Methuen (diplomat) the Treaty on 16 May 1703, a step of great significance in the War of the Spanish Succession. John, on his return from England, concluded a commercial treaty on 27 December 1703, opening Portugal to the English cloth trade in return for preferential rates of duty on the import of wine. How beneficial to either country the Treaty was in the long run has been debated; possibly its most important result was the development of the port wine trade, and it was later referred to humorously as "the Port-Wine Treaty". Methuen in later life increasingly suffered from gout and rheumatism;
Secret treaty financial arrangements, and 'military understandings'" are commonly cited as one of the causes of World War I. For example, the Reinsurance Treaty of June 1887 between the German Empire and the Russian Empire (negotiated by German Chancellor Otto von Bismarck in order for Germany to avoid a two-front war), was a "highly secret treaty" in which the two powers pledged a three-year period to remain neutral should the other become involved in a war with a third country, unless Germany attacked Russia's longstanding ally France or Russia attacked Germany's longstanding ally Austria-Hungary. The use of "secret agreements and undertakings between