Medieval Times

• In the more violent medieval society, most people were right-handed. People passed each other on the left in order to keep their sword arm free.
  
  

Horseback Safety

• Since horses are mounted on the left, it made more sense to travel on the left-hand side of the road. This way the rider could safely mount at the side of the road, rather than in the middle.
  
  

Papal Decree

• It is believed that in around 1300 AD, Pope Benefice decreed that his followers keep to the left.
  
  

Left Becomes Law

• In 1773, the British government introduced the General Highways Act. It had a keep left clause, which later became part of the 1835 Highways Bill.
  
  

Fun Fact

• Napoleon changed France's driving habits to the right because he was left-handed. He wanted his sword arm facing his enemies.