What is a dramatic irony? Discuss in reference to Julius Caesar

Dramatic irony is when the reader knows something that the characters don't. It's kind of like before anyone saw the film Titanic, they already knew Leonardo Decaprio and Kate Winslet would end up as fish food. The Very title (Tragedy of Julius Caesar) tells us that Caesar (and many other characters) are going to die and do not know it. An interesting point of dramatic irony is when Cassius talks about how this conspiracy will be repeated through the ages

Stoop then, and wash. How many ages hence

Shall this our lofty scene be acted over

In states unborn and accents yet unknown! Act 3

It's funny how we have seen this similar politically motivated scene filled with greed and lust for power played out through the centuries.