to deal with disciplined British regular troops. On August 12, 1776, Patriot Thomas Knowlton was given orders to form an elite group for reconnaissance and secret missions. Knowlton's Rangers, which included Nathan Hale, became the Army's first intelligence unit. When Washington was driven off Long Island he soon realized that he would need more than military might and amateur spies to defeat the British. He was committed to professionalizing military intelligence, and with the aid of Benjamin Tallmadge, they launched the six-man Culper spy ring. The efforts of Washington and the Culper Spy Ring substantially increased effective allocation and deployment of Continental regiments in the field. Over the course of the war Washington spent more than 10 percent of his total military funds on intelligence operations. Washington split his army into positions on Manhattan Island and across the East River in western Long Island. On August 27 at the Battle of Long Island, Howe outflanked Washington and forced him back to Brooklyn Heights, but he did not attempt to encircle Washington's forces. Through the night of August 28, General Henry Knox bombarded the British. Knowing they were up against overwhelming odds, Washington ordered the assembly of a war council on August 29; all agreed to retreat to Manhattan. Washington quickly had his troops assembled and ferried them across the East River to Manhattan on flat-bottomed freight boats without any losses in men or ordnance, leaving General Thomas Mifflin's regiments as a rearguard. General Howe officially met with a delegation from Congress at the September Staten Island Peace Conference, but it failed to conclude peace as the British delegates only had the authority to offer pardons and could not recognize independence. On September 15, Howe seized control of New York City when the British landed at Kip's Bay and unsuccessfully engaged the Americans at the Battle of Harlem Heights the following day. On October 18, Howe failed to encircle the Americans at the Battle of Pell's Point, and the Americans withdrew. Howe declined to close with Washington's army on October 28 at the Battle of White Plains, and instead attacked a hill that was of no strategic value. Washington's retreat isolated his remaining forces and the British captured Fort Washington on November 16. The British victory there amounted to Washington's most disastrous defeat with the loss of 3,000 prisoners. The remaining American regiments on Long Island fell back four days later.