The battle of Earth was by far the bloodiest battle of the Goa'uld War with tens of millions dying from the Goa'uld attack. The three Ha'taks arrived on the 31st of December 1936 the day of the signing of the Treaty of New Windsor and the day before the Asgard satellite meant to monitor the Sol System was sent into orbit. The three Ha'taks split up with one heading towards the Pacific Ocean, one in the heart of the Belgian Congo, and the last just north of the Azores. As the warships entered Earth's atmosphere only one was seen that being the one assigned to the North Atlantic region when a patrol by the Royal Portuguese Navy spotted the ship entering orbit. While the patrol was atomized a destroyer managed to get the message to Lisbon before the ship was destroyed allowing the Kingdom of Portugal to alert the United Empire and the Imperial Navy of the threat that had emerged. The Atlantic Fleet was immediately mobilized and set sail from across the British Isles to meet their foe in the Celtic Sea. The Hochseeflotte and Marine Nationale were both alerted and told to if possible aid the Imperial Navy which of course both choose to do.
The Ha'tak assigned to the Pacific came down over Johnson Atoll and promptly destroyed the island then began to head north towards their first target of Peral Harbour and Honolulu. As the Death Gliders and Al'kesh tore from their hangers to hunt down anything on the high seas the majority of the leadership of Hawaii were getting drunk in a rather large new year's party. The Ha'tak moved quickly towards Oahu and within an hour of arrival on Earth loomed over the darkened city and as the midnight fireworks went off they opened fire. Iolani Palace was utterly obliterated decapitating the majority of the American leadership in Hawaii. Then the Ha'tak moved west till they were over Ford Island where they once again opened fire destroying the entire naval facility of Peral Harbour. The blast so large that it destroyed both Iroquois point and Hickam field in their entirety leaving Peral Harbour open to the sea. From there the Ha'tak headed towards the Continental United States destroying every ship that they ran into on the way crippling the aid that could be sent to the devasted Hawaii which directly led to the status of Hawaii after the Battle of Earth.
The final Ha'tak came down in the middle of Katanga region of the Belgian Congo and proceeded to head annihilating anything they found. When the Belgian Air Force squadron stationed in Léopoldville scrambled to attack the Death Gliders and Al'kesh running rampart across the colony. The Belgian bullets against the Goa'uld plasma proved a bad mix the entire squadron was slaughtered and the Goa'uld continued north razing any settlement that they found to the ground. With the slaughter of the Belgian Air Force detachment the local government immediately called for aid from the United Empire in their holdings to the south east. The Rhodesian, Cape, Orange, and Natal Squadrons all set off while the Transvaal one acted as aa reserve. The British Death gliders managed to take down several Al'kesh but the Goa'uld had numbers on their side and the British were forced to concede Air Superiority over the Congo to the Goa'uld or else their entire force would be wiped out. The Goa'uld destruction of Léopoldville was anticlimactic for all the effort used to hold the Goa'uld off. The governor managed to escape the city before it was destroyed but the Goa'uld Death Gliders sunk the convoy killing him and the remaining government of the colony. The death of the governor and the obliteration of Léopoldville collapsed any and all authority in the Congo.
-Extract from Antony Beevor's book the Battle of Earth and the Aftermath
The destruction of Honolulu followed by Peral Harbour had eliminated the majority of the high-ranking leadership and the bombing raids by Al'kesh across the archipelago did not help the people of Hawaii. Across the island's society collapsed and the American control of the region was devasted allowing what happened next to continue. The Kingdom of Hawaii had been overthrown and annexed in 1895 and the claimants to the Hawaiian throne had been relegated to a life of obscurity. At the time of the attack on Honolulu the current claimant one David Kalākaua Kawānanakoa was hiking in the interior of Oahu and escaped the decapitation attack. When he returned to civilization the islands had collapsed into absolute anarchy and the people of Hawaii needed something to rally around. He was contacted by a group of Hawaiian Nationalists who managed to convince him to claim his true title. On the 4th of January he was declared King Kalākaua II of the Hawaiian Islands in the area that Iolani Palace had once stood. The Kingdom of Hawaii had returned to the islands and many railed to their banner in a chance to secure peace. Within two weeks the entire archipelago acknowledged his rule and he had to deal with the guns of the United States Navy instead of warring factions.
-Extract from Mary Beard's book The Return of the Kings
The second after the British government dispatched the Imperial Navy to attack the North Atlantic Ha'tak they began the long-planned Operation Conqueror the evacuation of the British Isles through the Stargate. The Royal Family and many other high-ranking officials were on New Windsor for the Treaty of New Windsor which saved the British government time to evacuate more important things such as the massive Naquadah stores that London, Leicester, and other major cities across the isles. While the British Government relocated to New Windsor Imperial Stargate Command alongside the Imperial Navy, and Imperial Air Force dragged out the big guns to hold off the Goa'uld until the Asgard arrived. IIET-1 alongside a detachment of Royal Marines were assigned to HIMS Hood which was leading the allied fleets against the Ha'tak. Though Tolkien and Sigurður Steelfangs were sent to ask the Asgard for help which would take a while to appear for those on the ground.
-Extract from Christopher Bowes's book The Bloody Wolves of the Stars: A history of Imperial Stargate Command