Final answer:
The quote "Beware the ides of March" was said by a soothsayer in Shakespeare's play "Julius Caesar".
Step-by-step explanation:
The quote "Beware the ides of March" was said by a soothsayer in Shakespeare's play "Julius Caesar". The soothsayer warns Julius Caesar about the ides of March which is the 15th of March, the day on which Caesar is later assassinated.