Vegetarianism has often been closely allied to radical movements in religion and philosophy. The mythical Hyperboreans lived for a thousand years on a vegetable diet, Pythagoras, Ovid and Seneca were vegetarians as were Sir Thomas More, John Evelyn, Leonardo da Vinci, Rousseau and Shelley. In the Dark Ages religious philosophers began to interpret Biblical texts looking for God's law on what people should eat. And not consuming blood but still eating meat became a great anxiety in the Christian West after the Renaissance. From the sixteenth century animal rights were rediscovered (it had been a concern of the Ancient World) and was linked to slavery and socialist ideals. In the twentieth century the idea that vegetarians lacked aggression took a severe blow after the example of Hitler as vegetarian. This history of vegetarianism could also be viewed as a history of radical movements which have questioned society's orthodoxy.