The news of Pedro II's signing of the abdication edict spread outside the palace, and some royalist officers such as Admiral Garcia, Lieutenant Colonel Ebel, and Baron Loreto realized that the situation in Rio de Janeiro was irreversible. …………

On the morning of the fourth day after the military coup, the republicans and democrats jointly announced the establishment of a republican government, elected Fonseca as the interim president of the new government, and the republican leader Morais as the speaker of the parliament.

In response, Auston, the British minister to Brazil, announced that the British government respects the wishes of the Brazilian people, recognizes the legitimacy of the new government, and is willing to carry out more in-depth communication with the Brazilian government on exchanges and cooperation between the two countries.

The change of power in a few days was completed by the largest territorial power in South America, and as the news of the successful coup d'état in the imperial capital spread throughout Brazil, important areas such as São Paulo, Paraná, and Goiás smoothly fell into the hands of the republican government.

When Admiral Garcia fled from Rio de Janeiro, Admiral García took advantage of the naval soldiers' allegiance to Princess Isabella and recruited five large warships, including two ironclads, to escort them away.

The Brazilian Navy has a total of five ironclad ships, and two main warships with a total displacement of 7,800 tons have been disorganized, which has reduced the combat effectiveness of the newly established Republic Navy by half in an instant.

The navy is a high-tech service, more than 80 percent of the middle and high-ranking officers of the Brazilian Navy are from the upper class, because of Pedro II's anachronistic reforms, most of the landlords and nobles gave up their support for him, but in the face of the end of imperial rule and the consequences of the serious weakening of political power, about forty percent of the naval officers and sailors chose to be loyal to the imperial crown prince, hoping to follow Princess Isabella to fight back to Rio de Janeiro and regain control of the central government.

On August 21, 1879, more than 300 officers and sailed out of the port without permission and sailed two medium-sized frigates to the northern seas, and on August 23, seven mid-level officers plotted to incite the navy soldiers to take control of the remaining three ironclads to defect to Isabella, only to be discovered by the alert commander of the garrison and stopped their actions in time.

The Navy's morale fluctuated, nearly half of the tonnage of its main warships was lost, and about 70 percent of its middle- and lower-ranking officers were lost.

On the one hand, the loss and weakening of naval strength led to the aggravation of the republican government's distrust of the navy, and a large number of naval officers from aristocratic families were ordered to prohibit boarding warships, and the remaining three ironclad ships and more than a dozen warships were concentrated in the military port of Rio de Janeiro.

On the other hand, Princess Isabella and her party of more than 2,000 people arrived

Salvador, the capital of Bahia, with the status of Crown Prince Isabella and the influence of royalist generals such as General Garcia, Duke Frobert, and Lieutenant Colonel Ebel in the army, more than 15,000 central troops stationed in El Salvador swore allegiance to Princess Isabella.

On August 22, the army was repaired and replenished for two days, and the royalist army stranded in the city of El Salvador quickly expanded to 25,000 men, and at noon on the same day, under the auspices of Duke Frobert, Princess Isabella crowned herself as the Empress of the Brazilian Empire, declaring the republican government to be a rebel, calling on the armies of all parts of Brazil to be loyal to the empire and eliminate the republican government.

At the succession ceremony, Empress Isabella appointed Duke Frobert as the Prime Minister of the Empire, overseeing the affairs of the Empire, conferred Garcia the Duke of Akaju, promoted his military rank to Marshal of the Empire, served as the commander-in-chief of the Imperial Army, conferred the title of Lieutenant Colonel Ebel as Count of the Empire, and promoted him to the rank of Major General, responsible for assisting Marshal Garcia in the management of the army.

Hastily completing the imperial succession ceremony, Marshal García and Major General Ebel led more than 14,000 troops and rode more than 40 large and small warships north to integrate the Brazilian troops in the northern states.

On 24 August, the Central Army, scattered in the states of Sergipe and Alagoas, joined Garcia's department, and on 25 August, Rear Admiral Ebel landed on the coast of Pernambuco on a warship, and in the evening of the same day, the royalist army entered the northern town of Recife, and the 6,000 troops stationed in the center were merged into the Ebel department.

By the end of August, most of the northern regions of Piauí, Rio Gro Norte, and Maranhão had been surrendered to the royalists, and the area under the Isabella government had expanded to nine states, and the number of Brazilian troops under royalist command had reached nearly 60,000.

In early September, the number of royalist troops in the north increased to 80,000, and the total number of troops under the republican government in the south exceeded 150,000.

The republican government controlled densely populated areas such as Rio de Janeiro and Via São Paulo, and had nearly twice as many troops as the royalists, but the republican government faced threats from Paraguay and Han.

At the beginning of the formation of the new government, López Jr., who had been planning for a long time, sent 40,000 troops to advance along the border between São Paulo and Minas Gerais, intending to crush the frontal Brazilian army and drive straight into Rio de Janeiro, bringing the core territory of the Brazilian Empire under Paraguay.

In less than two weeks, at the cost of 12,000 troops from all parts of the Republican Army, more than 60,000 troops were transferred to the states of São Paulo and Minasgi to block the continuous assault of the Paraguayan army.

On the front line of Paraná, when the news of the failure of the peace talks broke, the Han side stepped up the mobilization of troops to the northern frontier region, and by the beginning of September, the total number of troops gathered by the two sides in Paraná and Los Angeles (Santa Catarina) reached 90,000.

Excluding the forces pinned down by Han and Paraguay, the military strength used to deal with the royalists was about 70,000, and the Brazilian republican government did not have an advantage on a single front.

On September 3, 1879, the royalists avoided the land defense line of the republican government, and dispatched troops to attack Rio de Janeiro directly from the sea on warships, and the battle at sea was one-sided, the navy controlled by the republican government fought with the royalist fleet for less than half an hour, and the republican navy fleet was at an absolute disadvantage, in order to preserve the only remaining naval power of the republican government, the republican government ordered the naval fleet to retreat to the military port, and at the same time, according to the private agreement between the British and the Brazilian republican government, British Minister Alston ordered an expeditionary fleet to intervene in the Brazilian Civil War to prevent the royalist fleet from continuing to penetrate the coastal areas of Rio de Janeiro.

Britain intervened in the dispute between the two factions in Brazil and helped the republican government temporarily resolve the royalist maritime threat, but on the land side, the military offensive and deterrence and oppression of Paraguay and Han made the republican government worried all day long.

On September 5, Morais visited the British Minister Auston again, imploring the British Expeditionary Force to send troops to assist the Republican Army in blocking the Paraguayan army, and after the request was rejected by the British Minister, Morais solemnly made a request to Auston, hoping that the British Government would understand the difficulties of the Republican Government, and that the British Government would intervene to force Paraguay and Han to stop hostilities against Brazil and resume armistice negotiations.

In order to continue to implement the policy of balancing South America and reduce the losses caused by the miscalculation of the situation of the Brazilian civil war, the British government was forced to accept the request of the Brazilian republican government, lowered the conditions for peace talks, and took the initiative to invite Han and Paraguay to participate in the armistice negotiations.