it took three weeks for the news to cross the Atlantic. On 28 June 1812, was dispatched from Halifax to New York under a flag of truce. She anchored off Sandy Hook on July 9 and left three days later carrying a copy of the declaration of war, British ambassador to the United States Augustus Foster and consul Colonel Thomas Henry Barclay. She arrived in Halifax, Nova Scotia eight days later. The news of the declaration took even longer to reach London. British commander Isaac Brock in Upper Canada received the news much faster. He issued a proclamation alerting citizens to the state of war and urging all military personnel "to be vigilant in the discharge of their duty", so as to prevent communication with the enemy and to arrest anyone suspected of helping the Americans. He also issued orders to the commander of the British post at Fort St. Joseph to initiate offensive operations against American forces in northern Michigan who were not yet aware of their own government's declaration of war. The resulting Siege of Fort Mackinac on 17 July was the first major land engagement of the war and ended in an easy British victory. Course of war The war was conducted in three theatres: The Great Lakes and the Canadian frontier. At sea, principally the Atlantic Ocean and the American east coast. The Southern states and southwestern territories. Unpreparedness The war had been preceded by years of diplomatic dispute, yet neither side was ready for war when it came. Britain was heavily engaged in the Napoleonic Wars, most of the British Army was deployed in the Peninsular War in Portugal and Spain, and the Royal Navy was blockading most of the coast of Europe. The number of British regular troops present in Canada in July 1812 was officially 6,034, supported by additional Canadian militia. Throughout the war, the British War Secretary was Earl Bathurst, who had few troops to spare for reinforcing North America defences during the first two years of the war. He urged Lieutenant General George Prévost to maintain a defensive strategy. Prévost, who had the trust of the Canadians, followed these instructions and concentrated on defending Lower Canada at the expense of Upper Canada, which was more vulnerable to American attacks and allowed few offensive actions. Unlike campaigns along the east coast, Prevost had to operate with no support from the Royal Navy.