Laudanum is a solution of opium and alcohol with pain-relieving properties, first invented in a rough form by 16th century alchemist Paracelsus. Rediscovered in the late 17th century, it was widely available and prescribed enthusiastically as a treatment for various physical and psychological ailments, including insomnia. Opium's highly addictive properties were not fully recognised; its medicinal formulation as laudanum allowing respectable members of society to dabble in its recreational use.
Some quietly nurtured lifelong habits, like Romantic poet Samuel Taylor Coleridge, whose work is consequently sometimes regarded as having emerged from a drug-fuelled haze.
Online edition of Thomas de Quincey's 'Confessions of an English Opium Eater', (1822)