Pipes made from animal bones dating back to 2000BC provide early evidence that people sought ways to smoke or inhale substances. Various herbal texts from 1500AD onward described plant-based substances with narcotic or intoxicating effects. Attitudes continued to change over time, as poets and scientists in the 18th century experimented with various legal and illegal drugs, while temperance societies in the early 20th century pushed for restrictions on substances deemed dangerous or linked to social problems. International drug conventions in the 1960s further shaped global policies around controlled substances.