The size of a person’s world is only as big as the area that is known. Hunter-gatherers knew the area of the range of their game and where the good food was. Strangers would occasionally come by and tell tales of far away places. Generally, however, early man’s world extended only 20 to 40 km.

When agriculture became prevalent, that tied man to an even smaller area. One would not generally venture more than the distance that you could walk in one day and still return before night. This was because the domestic animals had to be tended, and it was dangerous to be out at night. There was little support for travelers – no hotels, no restaurants. Humankind was focused on the tribe or village. Those folks served as an extended family for support. The range of bronze age agricultural man was even less, perhaps only 10 or 20 km. Travel outside that range was usually to make war on a neighboring tribe.

Sometime in the fourth millenium B.C.E. man figured out how to ride the horse. Not only did the horse give greater mobility – a day’s ride carried you much further than walking, and the greater load carrying capacity of the horse let people carry food, tradegoods and weapons on the trip. It was now safer to travel beyond tribal lands and begin commerce. In addition to commerce, the horse was a fearsome weapon – used by the likes of Atilla the Hun. Travelers on horseback might bring goods and stories from hundreds of kilometers distant, but most people, excepting soldiers and traders still stick to their 20 km tribal turf.
About a thousand years later the wheel came into use. This allowed much greater load carrying capacity, as the bulk of the weight is not carried by the muscle power of the oxen or horse, just the motive power. Trade became more prevalent and the world became larger because it was now feasible to bring tradegoods over a much longer distance. Salt, spices, jewels, metals that are rare in one area are traded for goods that are rare in the other.

This treatise is somewhat Euro-West Asia and North Africa centered, but these same developments also occured in China, India and elsewhere on a similar timetable.

In another two thousand years, around 1000 B.C.E. the Phonecians opened the world up with sea trade. They were able to travel the Mediterranean in ships that could carry heavy cargoes, and withstand big storms. For the people who lived around the Mediterranean Sea, the world expanded to 3000 km or more, with the material, ideas and culture of people who live far away carried to and fro with the sailing traders.

Once trade on a large scale takes place, kings got the idea to build empires. Around 500 B.C.E. the Persian empire was formed which centered power in Asia Minor. This enlarged the world for the class of people in power, as that power has to be exerted over distance. With the end of the Persian empire in 328 B.C.E., the world once again shrunk as individual kingdoms mustered only regional power.

The Roman empire extended and improved the the concept of empire by building roads, ships and other means to improve communication. In this way the power of Rome was able to be readily exerted over great distances and the wealth of the entire empire could be returned to the center. The world to the Roman was the entire empire from Persia to Britan. The world was huge in Roman times in comparison to any time before.

The fall of Rome broke the world into many isolated pieces. Most people in the dark ages lived only in their village. The local king or count, only knew his county and the adjoining ones, and kings were little more than a stronger count who brokered alliances with his neighbors.

The rise of Christianity and the Catholic Church enforced the power of kings, and the people were attached to the land. For other than the clergy and royalty, the world was back to a 20 km range at best.

Not much happened until the plague or black death, then things really changed. Population througout Europe plummeted, and the skilled tradesmen, such as blacksmiths, farriers, loom makers, etc. were in short supply. One blacksmith would serve several villages. The world opened up to 50 km again. More people had independence, and money.
A hundred years later Gutenberg figured out how to mass produce writing. Literacy was very low at the time, since the plague did not spare the clergy and noble classes. When ideas can be had cheaply, the literacy is much more valuable. The world of ideas grew, so folks like Martin Luther were able to spread ideas far beyond the villages he visited.

Few educated people thought the world was flat, but the Atlantic Ocean seemed impassible. Columbus made the world larger by bringing back the knowledge that there were riches to be had on the other side of the Sea. The world grew by 5,000 km.

For the average person, the world was still largely the village, the county and the nation. The Spanish, French and English empires spanned the globe. It was still a major effort to travel to India or America, but the riches of trade were worth it. It still took weeks for the word of something happening in America to get to Europe. What was happening in the colonies was of little concern to the average person, unless they wore silk or cotton or smoked tobacco.

In America, Horace Greeley said “Go west young man”. Going west meant a permanent break with life back east. It took months to travel just from St Louis to the west coast. The likelihood is that you will never return from the trip, since the trail west was so daunting, and the opportunity so great. The railroads changed that, making it a relatively safe passage from coast to coast in a week or so. Folks back east could get mail from their family in California, and those on the west coast could get manufactured goods from the east. When someone went west before the train connected America, their entire world moved. New England became just a memory, not somewhere to return. The train changed all that.

The train drew lines of closeness. If you were on a rail line, you could travel easily, if you were off the line, you