Final answer:
The poem "The Doubt of Future Foes" speaks to the unseen threats and rival claims to the throne faced by Queen Elizabeth I, reflecting real possibilities of internal strife and betrayal within royal courts during her reign.
Step-by-step explanation:
The queen's major future foe in "The Doubt of Future Foes" is not explicitly named in the poem but is widely interpreted to refer to threats to the throne faced by Queen Elizabeth I, including the rival claims of Mary, Queen of Scots. The poem reflects upon the various challenges and schemes that Elizabeth might have to contend with, emphasizing on the idea of internal strife and betrayal within royal courts. These themes suggest an environment where intrigue and power struggles were ever-present, as queen's faced adversaries both seen and unseen, such as rival claimants to the throne and their supporters.