Our history—a different kind of war.

I like to do historical research.  I ran across Washington’s Letters in the National Archives, and I was intrigued by how different war was conducted in the Revolutionary War—244 years ago (that is about ten generations).  Here’s the story.

22 September, 1777… Washington writes to one of his colonels, a Colonel George Gibson, who was from Pennsylvania but commanded the First Virginia Regiment.  Washington writes from Camp on the Reading Road, ten miles from Philadelphia. [An exerpt from George Washington’s handwritten letter, transcribed by Marsha Arzberger]. 

I wrote to you ten days ago directing you to join this army with the utmost expedition.  But our situation has been so much changed by a variety of circumstances since that time that I think it proper to inform you that we are at present here and are moving up the country towards Reading as the enemy are moving up that way from the west side of [city unreadable].  I would recommend to you to march from Lancaster to Reading … I would advise you to keep an intelligence officer ahead, not only to find out where they are, but also where our army is. You may by this means save much needless marching. Let me know as soon as possible where you are. [The letter is signed: Sir, your most obedient servant, G. Washington.

Imagine all communications were by written letter, delivered by courier.  The general did not know the precise location of his army units, nor where the enemy was.  How did General Washington direct this war?