The intense rivalry between Habsburg Spain and Elizabethan England (1558–1603) stemmed from:
Spain: Champion of Catholicism, Counter-Reformation. England: Protestant under Elizabeth I (excommunicated 1570). Religious identity became geopolitical allegiance.
Both sought dominance in the Americas and Caribbean. English privateers (Drake, Hawkins) raided Spanish treasure fleets and settlements, challenging Spain's monopoly.
Conflicting claims in North America (e.g., Roanoke, Florida), the Caribbean, and the Pacific. Spain viewed English presence as trespass.
Philip II of Spain (Catholic) considered himself heir to the English throne via descent from John of Gaunt. Elizabeth's unmarried, childless status made succession a flashpoint.
These conflicts set the stage for centuries of imperial competition.