I remember a line like "the uncertain glory of an April day" that described an elusive victory in battle. I thought it was from Julius Caesar but I have not been able to find it in any play! Can you please, please help me?
The line you're looking for is the following:
O, how this spring of love resembleth The uncertain glory of an April day Which now shows all the beauty of the sun, And by and by a cloud takes all away!
It is from Act I, Scene III of William Shakespeare's play The Two Gentlemen of Verona. It is spoken by Proteus, one of the two gentlemen.