And you are still wrong probably ... this is one of the earlier descriptions of the effect, I'm pretty sure gravity is one of the very first things everybody discovers when they are just born, it takes some time to consious experience it off course.
I'm 100% confident that more people knew about the force of attraction off the earth, thus gravity, way way earlier. I think Matt is still right with his 'Columbus discovering the Ocean-comparison'. A better statement would be that 'the first one, or at least from which we've found the text/inscription the first, to write down a description of the force of attraction we now call gravity (since Newton? naaw somehow I think that's older too, but not sure) was the Indian astronomer Brahmagupta. But there are plenty of cultures before 628 who used gravity in their advantage, so in my opinion they must have known.

Cheers