Some flags from my timeline— I only have one chapter written and we're nowhere even close to Latin American independence, but I've been really into that era of history for a bit now and just had to scratch down a few flags. Read clockwise, these are the flags of Brazil ITTL from first to last. Though the Napoleonic era is completely different (and the Napoleonic Wars as we know them don't even happen), economic war with Britain still leads Napoleon to invade Portugal, sending their royal family packing to Brazil. However, unlike in OTL, they would never return.
First up in the top-left is the "Tripartite Kingdom" or "Dual Monarchy" of Portugal, the Algarve, and Brazil
. This flag incorporated a green and gold armillary sphere and two green bars into the older flag of the Kingdom of Portugal. The armillary sphere was meant to represent Brazil, as it was a common sight on ships going to and from the colony and so was seen as an unofficial symbol of the region. The green bars were sometimes included and sometimes not included in actual use. Technically, the green bars were for the flag representing the royal household, as green was the color that represented the House of Braganza, but its use by both the national government in Rio de Janeiro and the nascent Milícia Real
meant that the bars are more commonly associated with the Tripartite Kingdom than not. It is also of note that the name "Tripartite Kingdom" and "Dual Monarchy" were not in wide use at the time, and are merely historical designations to distinguish the country from prior governments in which Portugal was the dominant force and later governments in which Brazil was the dominant force. While some historians prefer to recognize the Algarve as a separate kingdom, those of the realist school consider it merely ornamental and do not acknowledge it in their naming conventions. At the time, the Tripartite Kingdom was usually referred to as "Portugal" internationally and as "Brazil" by the citizens it actually ruled over.
Sooner rather than later, tensions grew between the Tripartite court and its Brazilian subjects. These subjects may have referred to the nation as "Brazil," but their government was definitively "the Portuguese." And, though it eventually became obvious that the court wouldn't be returning to Lisbon as quickly as they planned for, the Kingdom stubbornly refused to embrace their new reality. That is, they stubbornly refused to embrace their new reality by their own volition. The Summer Uprising in Rio de Janeiro flew a makeshift banner of three blue bars on a white field, and the interim military-republican government that seized the Portuguese court kept that flag. When the new Brazilian Assembly decided on keeping the royal family in charge as part of a liberal constitutionalist empire, they added a canton of the coat of arms, imposed on a yellow rhombus on a green square. The green still represented the House of Braganza, while the yellow represented the Assembly literally imposed on top of the old monarchy (as yellow was the color associated with its leading faction, the "Yellow Vests" in reference to their cavalry officer uniforms). Soon afterwards, the Crown Jewels were updated, and the crown on the coat of arms was changed to reflect that. This flag was the first (unofficial) banner of the (First) Empire of Brazil, Portugal, and the Algarve
. Brazil has been the first territory listed in the name ever since.
Upon the death of Emperor Dom João I, Emperor Dom Pedro I rose to power. However, the young emperor was still unmarried at the time of ascension to the throne. Pedro I was ambitious, and he spent almost a decade of bachelorhood completely unconcerned with marriage, instead increasing the Emperor's popularity and power in relation to the Assembly through shrewd politicking and leadership during Brazil's military campaigns. When he finally did marry, it was to the young and equally-ambitious Princess of Illyria, Marie-Germaine Bonaparte. It was a marriage of love, and was politically inconvenient for both of them. Almost immediately after his marriage, Pedro entered a sweeping reform bill into debate in the Assembly that would establish a formalize constitution, centralize the government, place severe limitations on the slave trade, declare Rio de Janeiro the permanent seat of the government, and limit his own powers as emperor. With public pressure from Rio de Janeiro and a majority in favor of most of the bill's contents, it passed, establishing the Second Empire of Brazil, Portugal, and the Algarve
. A new flag was introduced as well, this also (finally) formal and official. Replacing the white and blue's association with the now-deeply-unpopular First Assembly are stripes of yellow (at this point even more definitively a color of the liberal, centralist faction in Brazilian politics and perhaps even Brazil itself) and deep royal blue, either representing the House of Bonaparte or the hope of a restoration of control in Portugal depending on who you ask.
By far the flag used the longest, this one was installed later into Emperor Pedro I's life. With a growing colonial presence in Africa, Pedro sought to symbolically represent its inclusion in the empire. And so, after ratification in the Assembly and with the approval of the Public Ministers, the "Third Empire" was retitled as the Empire of Brazil, Portugal, the Lesser Equator, and the Eastern Islands
, with its longer official name also including its territories in Goa, Guinea, Macau, and Cabo Verde. Notably absent from this title is the Kingdom of the Algarve, which had actually been ruled separately from Portugal back on the mainland by the Godoys for years now. Pedro had become friends with King Manuel II, and while the idea of designating the African colonies to "the Algarve" was floated, Pedro wanted to send a signal of compromise and rapprochement with the continent by abandoning that particular claim. This change in state structure and symbology coincided with a reshuffling of the elements of its flag. The canton was moved to the center of the flag, stressing the importance of both the monarchy and its subordination to liberal institutions, while the stripes (now vertical) flanked it, representing the vast stretch of the Empire from east to west, with Brazil itself in the center.