The hop part is a bit more interesting. The strong beers of the time weren’t enough to keep the beer from getting infected. However, hops are a natural preservative. The oils have antibiotic properties. They were initially used as a preservative for weak British ales and the taste was a side effect but not necessarily the desired effect. When they had trouble shipping their beers across the world, they would pack the beer full of hops so it would make the trip. Eventually, Brits in India developed a taste for the bitter beer that was shipped to them and a beer style was born.