Aglianico is a grape variety grown in Southern Italy, mostly in Campania and Bascilicata. Most experts consider Aglianico to be one of Italy's "noble" varieties, alongside Sangiovese and Nebbiolo. It is the grape that makes Taurasi, the most famous red wine from south of Tuscany.
They are both made 100% from Nebbiolo grown in the Langhe. But Barolo and Barbaresco are clearly not the same wine.
The easy answer is the legal one: Barolo and Barbaresco are two different DOCs. They are located in slightly different parts of the Langhe (see the map above).
There are slightly different rules that they have to follow -- for example Barolos have to be aged for 38 months, of which at least 18 months are in barrel, while Barbaresco only requires 26 months, of which 9 must be in barrel. Barolos have to hit 13% alcohol and Barbarescos only 12.5%.
I guess that sort of thing is great to know for your WSET exam, but it doesn't get you into the heart and soul of how these wines are distinct. Hopefully this list of five key differences will help you do that:
