The poppy is embedded in folklore. Some people believed that they cured headaches and protected them from lightning. However, other people thought that poppies brought on headaches and caused thunderstorms.Because poppies are so easy to identify, they have featured in many herbals throughout history. Herbals are books that contain the names and descriptions of plants, their various uses as well as legends associated with them. William Salesbury, author of the first book published in Welsh, wrote a herbal between 1568 and 1574. He mentions that heads of the poppy cause sleep and cure various ailments. John Gerard in his herbal of 1597, however, warns that 'Opium, or the harde juice of Poppie ... too plentifully taken doth also bring death...'