Spanish colonialism on Cipangu and Magellania began with the discovery of Magellania by its namesake Ferdinand Magellan in 1521. The Spanish were the first Europeans to establish a permanent foothold on the eight continent. This early dominance was shortlived, as soon as the 17th century, indigenous resistance successfully reverted many Spanish colonial gains. Elsewhere new colonial powers like Great Britain and the Netherlands took control of Spanish territories.
The continent of Magellania was first in January 1521 by Ferdinand Magellan. Magellan landed in a place, where the city of Puerto de Magellan would be founded. From there on Magellan continued his journey, not yet realising that he had discovered another full continent. The islands he traversed would be known as the Magellanian Isles. This name would be applied to both continents at first, until the voyage of Pánfilo de Narváez in 1528. Narváez received the mission to find the land of Cipangu (then the name for Japan), as it had not yet been discovered by Europeans. Narváez landed on the eastern coast of the northern continent and called it Cipangu henceforth. This mistake, which was of the same nature as naming the Americas India, eventually stuck.
The initial phase of Spanish colonialism was similar to that in the Americas. The Spanish founded several cities or renamed conquered indigenous cities. These include Puerto de Magellan, Cabo de Mapete, San Ignacio, Ciudad de Narváez, Asunción, Toledo del Occidente, Ciudad de Fuca and many more. One of the main goals of these colonies was to keep oceanic trade routes save between the Americas and Asia.
One oddity among the cities founded by the Spanish Empire is the colony of Nueva Tlaxcalla. In 1566, the Tlaxcallan nobleman Lorenzo de Xicotencatl III. decided to use the liberties granted to his people to emigrate from Mexico towards Cipangu. They decided upon a peninsular direction counter to the Mexican coast and founded the city of Nueva Tlaxcalla. The majority of this group were indigenous Nahua and their families, followed by a number of Spanish friars and some soldiers. The Tlaxcaltecs settled around the peninsular and preserved Nahuatl as commonly spoken language there.
In 1570 the Spanish authorities decided to reorganize their Magellanian and Cipanguan possessions. In this process the Viceroyalty of the Magellanian Isles was established. The city of Puerto de Magellan became its capital. The exception to this reorganization was the colony of Nueva Tlaxcalla, which remained part of Mexico and the Viceroyalty of New Spain, giving it de-facto an autonomous status.
In 1599 another new Viceroyalty was established in form of the Viceroyalty of Cipangu. Its capital became the city of Toledo del Occidente. One reason for this split were the large differences between the Cipanguan and Austronesian inhabitants of the colonies.
The height of the Spanish Empire on Cipangu and Magellania was undoubtly during the 17th century. Cities such as Cabo de Mapete and Santa-Maria-del-Occidente grew in wealth and power, through the American-Asian trade. In the north, the Spanish gained several powerful client kingdoms that made it possible for them to extend their reach into the northern Balboan ocean (North Pacific) as well.
However the Spanish influence also received a lot of pushback, especially from the Kingdom of Managi, and the Zhughaw Confederation, which consolidated in 1642. These two polities were especially opposed to the aggressive missionary efforts of Spanish friars. Soon they would begin to outlaw Christianity within their own realms. In the south on Magellania, the British privateer and explorer Francis Drake had previously laid the foundations for British colonies on Magellania. The British and the Dutch would eventually make their own treaties to split up Magellania for themselves, disregarding Spanish claims.
However, the catastrophe for the Spanish colonies would come twofold. The first major catastrophe was the War of Spanish Succession from 1701-1714. Britain would join the Habsburg side eventually and in 1710 begin to seize control of Spanish territories on Magellania. After the war, Britain would keep them. The former Spanish colony of Nuevo Léon would be remade into the North and South Liony under British rule.
The second and far larger catastrophe was the Great Rebellion of the Northern Alliance. In 1715 the Kingdom of Managi would attack and successfully conquer Ciudad de Fuca, and rename it into Pogangi. Later, driven by these events, several indigenous vassals would seek freedom from Spanish rule. They'd form the Northern Alliance and push out the Spanish. The result was the complete destruction of the Viceroyalty of Cipangu, which was officially dissolved in 1725.
The later phase of Spanish colonialism is mainly marked by decline. The wealthy cities along the Sea of Magellan continued to be influential and powerful through trade, but the Spanish colonies essentially stopped expanding. Most of the claimed territory remained sparsely populated and hardly under Spanish control at all. Meanwhile other colonial powers began to trade Spanish colonies and claims amongst each other. For example the British gifted several territories to Austria and Hannover. During the 19th century other Spanish colonies would be taken up by Britain and eventually also the German Empire.
In the late 19th century, the Spanish possessions are limited to the Magellanians Isles and the Peruvian Isles. The colony of Nueva Tlaxcalla was eventually taken by the renewed Habsburg Empire of Mexico under Maximilian I.