Final answer:
Dom João VI, Pedro I, and Pedro II were significant figures in the establishment and maintenance of the Brazilian Empire, transitioning from a Portuguese colony to an independent empire with Pedro I, and achieving stability under Pedro II.
Step-by-step explanation:
The significance of Dom João, Pedro I, and Pedro II lies in their roles in the foundation and consolidation of the Brazilian Empire. Dom João VI, fleeing from Napoleon's invasion, established the Portuguese court in Rio de Janeiro, elevating Brazil's status. His son, Pedro I, declared Brazil's independence from Portugal in 1822 and became its first emperor. He faced political challenges, including disagreements over slavery and the constitution. After abdicating in 1831 in favor of his son due to his autocratic rule and the influence of the July Revolution in France, Pedro II ascended the throne. He reigned for a long period, marking a time of domestic stability and international recognition for Brazil.