Years later, someone built a pig sty onto it and drained the pig sty into the nettle patch. Later still, the original wall blew over and so on. Each event, which may have taken a short or long time to accomplish, leaves a context, a deposit of material, on the site.
Years later, someone constructed a pig pen onto it and drained the pig pen into the nettle patch. Later still, the original wall collapsed and so on. Each event, which may have taken a short or long time to occur, leaves a context, a deposit of material, at the site.