Explanation: In 1497, under the Treaty of Tordesillas (1494), the rulers of Portugal and Spain divided the non-Christian world between them by an imaginary line in the Atlantic, some 1,300 miles west of the Cape Verde Islands.

• Under the treaty, Portugal could claim and occupy everything to the east of the line while Spain could claim everything to the west.
• The situation was thus prepared for the Portuguese incursions into the waters around India.

Source: Spectrum Modern India