Columbus, therefore, came to the conclusion that the line of no variation was a fixed geographical line, or boundary, between the Eastern and Western Hemispheres.

In the bull of May, 1493, Pope Alexander VI.

accordingly adopted this line as the perpetual boundary between the possessions of Spain and Portugal, in his settlement of the disputes of those nations.

Subsequently, however, it was discovered that the line was moving eastward.

It coincided with the meridian of London in 1662.
By the papal bull the Portuguese possessions were limited to the east of the line of no variation.