Explanation:

In 1786, Lord Cornwallis was appointed as Governor-General and commander in chief in India. He is known for having instituted land , judiciary and administrative reforms and reorganized the British army and administration. He had a demand that powers of the Governor-General be enlarged to empower him, in special cases, to override the majority of his Council and act on his own special responsibility. The Act of 1786 was enacted to give him the power of working as Both Governor General & Commander in Chief. Thus via act of 1786, Cornwallis became the first effective ruler of British India under the authority of Board of Control and the Court of Directors.