The Anglo-Saxons lived and ruled in Britain between 1500 and 1,000 years ago.
They were people from north-western Europe (the lands that we now call Denmark, north-western Germany and The Netherlands) who began to invade England while the Romans were still in control, but when their power was weak. That was just over 1500 years ago.
England was ruled by Anglo-Saxons for over 500 years.