Until the coming of the railroad in mid-19th century, travel on land was difficult and very slow. For the most part travel was done on foot as few were able to afford horses or oxen to pull their wagons. In the Mediterranean world there were the Roman roads but as the centuries went on many of these were not kept up.
People who traveled usually did so in groups for protection. The distance between the inns on the road was from 20 to 25 miles, and the travelers had to reach the safety of the villages before nightfall. If they did not arrive by nightfall, their goods could be stolen by the local bands of thieves. As there was no long distant communication the travelers never knew if the inn they were walking to had enough food. When they arrived they were served what was available, and went hungry if there was famine in the area. Everyone slept in the same large room in the inn, and any coins or valuables the travelers carried had to be kept hidden.
Travel by ship was little better. There were no luxury cabins, the galleys were carrying sand or wheat if they were sailing north from Egypt, silver or olive oil if they were traveling south from Greece and Rome. Travelers stayed on deck. They had to supply their own food and shelter. In rough weather the cooking fires were put out and the travelers had to eat whatever they carried cold.
In this context we can understand how important it was for travelers to have a saint to whom they could petition for protection. Their prayers of petition went most often to St Christopher. There are many stories about St Christopher who lived in the Eastern Mediterranean world. He is said to have been a large and strong man, looking for the most powerful person to serve. For a while he thought he had found that in Satan leading him to the the life of a thief. He spent some time with a band of robbers preying on the travelers. When he saw one of the thieves making the Sign of the Cross, Christopher discovered that the man feared Jesus more than Satan. Christopher left the gang to serve this more powerful Lord Jesus.
Instead of preying on travelers, Christopher lived by a river to aid those who needed to cross. One day a child asked to be carried to the other side. As Christopher carried the child across, the child became heavier and heavier. Christopher barely made it to the other side. Thinking that the burden of the whole world could not be greater than that child, Christopher discovered he had carried the Lord Jesus Christ. In his aid to travelers every day, Christopher was carrying out the work of Christ.
St Christopher was eventually martyred by a pagan king. But the memory of his service to others in their travels was kept alive. The image of St Christopher carrying the Christ Child is his most popular image in holy cards, stained glass windows, and statues of every size. Many people wear a St. Christopher medal to help keep them safe when traveling.
St Christopher is one of the most popular of saints, and his intercession is petitioned by travelers, soldiers, sailors, those caught in storms, and transportation workers. He no longer has a universally celebrated feast day in the Roman Calendar, but is remembered by many local churches.