A century is a period of a hundred years. Generally, an easy rule to know the century knowing the year you add 1 to the first two digits unless it ends in double zero, it belongs to the century of its two first digits. For example, in the case above, we should add 1 to 10, so we have the 11th century. But, if it was the year 1200, for example, we would be talking about the 12th century not the 13th one. William the conqueror was the winner of the Battle of Hastings against King Harold, which gave him the throne and was crowned on Christmas 1066.
Many northern people believed that "its economic focus should become industrial rather than agricultural," since many people in the North were opposed to slavery, which was the dominant driving force of the agricultural economy.