Great question - it is actually an idiom, which means, "the thing I expected, hoped or feared would happen". For instance you can say, "I knew he'd be able to learn Italian, I said as much at the time" (i.e. "I said I expected him to be able to learn Italian at the time") It also has a slightly different use in sentences like, "Please have me to stay next week, you know I'd do as much for you", where it means "the same".