Tokyo, now one of the largest and most populated cities in the world, came from a small fishing village which held a strategical position to the water (land, sea and river routes) in the Kantō province.
From 1603 to 1868 is the period in Japan often referred to as the Edo Period, which was marked by continuous growth now that the country had finally unified. Edo was the old name for Tokyo, which came from Edo Shigenaga, a military governor of a large province who built his own castle there, called Edojuku (Edo castle).
Much of the culture and literature flourished in this period, as Japan adopted strict isolationist policies, stabilized its population and ended a period of internal fighting between the various warlords.
The period started with Tokugawa Ieyasu becoming the shogun (military dictator) of Japan and selecting Edo as his headquarter. The strength of his shogunate over the whole country meant that the emperor, located in Kyoto, was effectively powerless.
This period came to an end in 1868 when the pro-emperor army defeated the supporters of the shogunate in the Boshin War. The government had been growing more powerful for a while and events sparked by the forced treaty upon the opening of Japan helped to bring about this change.
Emperor Meiji moved to Edo and started a new period of reforms and innovation for Japan, called the Meiji Period or Meiji Restoration, which led to the current state of Japan after more than 200 years of isolation.