Line of Demarcation, boundary established by Pope Alexander VI on May 4, 1493 to define the spheres of Spanish and Portuguese possessions in the New World (North and South America). The line ran from north to south 100 leagues (about 483 km/about 300 mi) west of the Azores and Cape Verde Islands. All new lands lying east of this line were to belong to Portugal; all those to the west to Spain. Portuguese dissatisfaction with this arrangement led to the Treaty of Tordesillas (1494) between Portugal and Spain, in which a new line of demarcation, sanctioned by Pope Julius II in 1506, was set 370 leagues (about 1770 km/about 1110 mi) west of the Cape Verde Islands. As a result of this change, Brazil became a Portuguese possession. The line of demarcation, and all agreements based on it, were abrogated in 1750 by a treaty settling a dispute over the south-western boundary of Brazil. The 1750 treaty was in turn abrogated in 1761. Further disputes between the two countries were settled by a new treaty in 1779.