India and Nepal commenced modern diplomatic relations in 1950 with the Indo-Nepal Treaty of Peace and Friendship. Along with the treaty, there were secret letters that described the security relations between India and Nepal and also an accord that governed bilateral trade as well as trade passing through India. The treaty and the letters stated that neither country shall stand by and watch if one of the other is attacked by a foreign aggressor. They also mandated both countries to inform one another of any series issue or friction with any neighbour state which could cause some fissure in the friendly relations between India and Nepal. This brought about a special relationship and Nepalese were granted equal educational and economic opportunities as Indian citizens, and Indian nationals were also accorded preferential treatment in Nepal as compared to people of other nationalities.