On July 18, 1997, the International Centre for Settlement of Investment Disputes (ICSID or the Centre) received from Mr. Emilio Agustín Maffezini a Request for Arbitration against the Kingdom of Spain. The request concerned a dispute arising from treatment allegedly received by Mr. Maffezini from Spanish entities, in connection with his investment in an enterprise for the production and distribution of chemical products in the Spanish region of Galicia. In his request the Claimant invoked the provisions of the 1991 “Agreement for the Reciprocal Promotion and Protection of Investments between the Kingdom of Spain and the Argentine Republic” (the Argentine–Spain Bilateral Investment Treaty or BIT).1 The request also invoked, by way of a most–favored–nation (MFN) clause in the Argentine–Spain BIT, the provisions of a 1991 bilateral investment treaty between the Republic of Chile (Chile) and Spain.