The gittern is an old-fashioned musical instrument that is similar to a guitar. It is small and has strings that you pluck with your fingers. It was popular during the Middle Ages, a time long ago when boys and girls didn't have all the cool toys and technology we have today. People who played the gittern were often musicians who traveled from town to town singing songs and playing music to entertain people. It's kind of like the guitar you might see a musician playing on the street today, but smaller and older.