The term "evangelical" is used to describe a particular set of Christian beliefs, and is generally considered orthogonal to denominations - you could get, for example, evangelical Anglicans and non-evangelical Anglicans. I've also heard the term used (or at least implied) of Christians from past centuries who ascribe to those same beliefs. For example, I'm not sure if the likes of Spurgeon or Wesley would have called themselves "Evangelical", but they are often spoken of in those terms.
When did the particular set of beliefs currently referred to as "evangelicalism" gain that name, and what was the historic context that required the distinction?