The treaty map of Tordesillas shows flags of Spain and Portugal. Illustrations 10 and 11. The Spanish flag, in this place,shows brown lions on a white field--and white castles, not gold, on the red field.
The five circles on the Portuguese map are apparently explained hy a record of the Franciscan friar of 1350 (q.v.) which says the five white circles on the then Portuguese map represented the five wounds of the Saviour.