he Old-English word for a settlement was a 'tun' which over time became the word we use today, town. The number and size of towns started to grow after the Norman Conquest in 1066 but in the medieval period agriculture was the most important job that a person could do. Even those who lived in towns would have worked in the fields around them. At harvest-time other trades would be suspended so that as many hands as possible could gather the crops. Many towns grew up where there was a natural advantage, e.g. at natural harbours, river crossings and at major crossroads where people could set up shops to sell to passers by. Some of these towns have names that reflect their position such as Cambridge and Oxford where easy river crossings could be controlled.