Drudge

Someone who performs servile, monotonous, and difficult work.
A hack.

"Up, and pleased mightily with what my poor wife hath been doing these eight or ten days with her owne hands like a drudge, in fitting the new hangings of our bedchamber of blue and putting the old red ones into my dressing-room; and so by coach to White Hall."

Samuel Pepys, Diary (January 26, 1666)