Our full title is "Evangeline: A Tale of Acadie." Of those five words, two of them are pretty important. We'll let you wrestle with "A," "Tale" (story), and "of" on your own. For now, let's discuss "Evangeline":
To sum up: she's the star of our story. She's sweet, beautiful, and devoted. She's the one we all root for and it's her sorrow and heartache that we feel the most. Poor Evangeline really goes through the ringer in her long, drawn-out, and ultimately fruitless pursuit of her near-husband Gabriel. And yet, she keeps going. She's a model of perseverance and faith. She really shows us what the power of love (no, not that one) can do. The title, then, draws our attention to her right from the get-go.
As for "Acadie," there are two things to note here. Thing 1: this is the name of a place that no longer exists. It's now (in Longfellow's day and still in ours) called Nova Scotia. So we learn quickly from this title that we're in for a history lesson. More importantly, Thing 2 to notice is that this is not "Acadia," but "Acadie"—which is how the French referred to their own colony. This word choice alerts us to the point of view we'll be encountering in this poem: the French one. This is going to be a tale in which the French are the good guys and the English are the bad guys (apparently, the native groups who lived there even before the French showed up aren't going to get a mention).
To sum up, our title does a great job of telling us whom to root for. So pop on your berets, break out your baguettes, and slip on those "Team Evangeline" t-shirts.