powerful navy made up of two ships of the line and ten frigates in addition to corvettes, steamships, and other ships for a total of at least 80 warships in peacetime. Quelling rebellions, 1831–49 During the 58-year reign of Dom Pedro II the Brazilian Navy achieved its greatest strength in relation to navies around the world. The Arsenal, Navy department, and the Naval Jail were improved and the Imperial Mariner Corps (formed then by volunteers) was created. Steam navigation was definitively adopted. Brazil quickly modernized the fleet acquiring ships from foreign sources while also constructing others locally. Brazil's Navy substituted the old smoothbore cannons for new ones with rifled barrels, which were more accurate and had longer ranges. Improvements were also made in the Arsenals (shipyards) and naval bases, which were equipped with new workshops. Ships were constructed in the Arsenal of the Navy in Rio de Janeiro, Salvador, Recife, Santos, Niterói and Pelotas. The Armada also successfully fought against all revolts that occurred during the Regency (where it made blockades and transported the Army troops) including: Cabanagem, Ragamuffin War, Sabinada, Balaiada, amongst others. When Emperor Pedro II was declared of legal age and assumed his constitutional prerogatives in 1840, the Armada had over 90 warships: six frigates, seven corvettes, two barque-schooners, six brigs, eight brig-schooners, 16 gunboats, 12 schooners, seven armed brigantine-schooners, six steam barques, three transport ships, two armed luggers, two cutters and thirteen larger boats. During the 1850s the State Secretary, the Accounting Department of the Navy, the Headquarters of the Navy and the Naval Academy were reorganized and improved. New ships were purchased and the ports administrations were better equipped. The Imperial Mariner Corps was definitively regularized and the Marine Corps was created, taking the place of the Naval Artillery. The Service of Assistance for Invalids was also established, along with several schools for sailors and craftsmen. Platine Wars, 1849–70 The conflicts in the Platine region did not cease after the war of 1825. The anarchy caused by the despotic Rosas and his desire to subdue Bolívia, Uruguay and Paraguay forced Brazil to intercede. The Brazilian Government sent a naval force of 17 warships (a ship of the line, 10 corvettes and six steamships) commanded by the veteran John Pascoe Grenfell. The Brazilian fleet succeeded in passing through the Argentine line of defence in The Tonelero Pass under heavy attack and transported the troops to the