They summon familiars from day one, absorb percentages of hostile spells, and gain resistance to magic. Their political, diplomatic nature also results in a speech bonus, while they also get one for Alchemy.
Playing a Breton in Skyrim gives major bonuses to major magic skills like Conjuration, Alteration, Illusion, and Restoration. That could have been just slowly cut or part of the magic in their blood diluting over the years, but if there is one thing that is certain about Bretons in Skyrim and anywhere, they are powerful with magic. Once upon a time, Bretons were said to be taller than the average person, but it’s unsure why that was changed. As their ancestors and lineage come from a selection of elven and menfolk, they have strengths akin to both. Bretons, or Manmeri, are essentially half-elves.