Nusantara is a term given to the collection of Islands that dotted Southeast Asia, encompassing well over 25,000 distinct landmasses connected by an archipelagical sea. In the middle of the most crowded maritime route are the nations of Indonesia, Singapore, Malaysia, and Brunei, the three of which are muslim-majority countries. Alas, how does this region, where Buddhism and Hinduism was much prevalent in the past, coupled with its geographically distant location with the Arabian peninsula come to be populated by muslims? And how does it affect both the local culture and political stance? In this, we need to look back to the old seafaring nations of Nusantara.
It started back in the 7th to 8th century, the feuding states of maritime Southeast Asia struggle for both territory, power and legitimacy as they try and let their rule known to the land. In this, they work up their framework on how best to unite the vast and diverse land. Most popularly, these upstart kingdoms would receive their spiritual supremacy via a new religion brought by the Indian traders, Hinduism and Buddhism where its followers revere their leaders as manifestations of "gods" in the material realm, with this ensuring internal stability and peace of the realm. Meanwhile, legitimizing their political (outwardly) rule with diplomatic relations of the Middle Kingdom, the dynasties of China.
This sort of sociopolitical framework of governance would dominate the archipelagic states for the better part of the next 5 centuries, giving birth to kingdoms such as Singhasari, Srivijaya, and most notably, Majapahit. States formed over this "Mandala" system would dominate maritime Southeast Asia until the advent of a new wind of traders, one which would shook the spiritual realm of these nations.
The meteoric rise of a new religion in the middle east has shaken this old centre of civilization, from the ashes of the old kingdoms of Babylon and Persia, a new civilization was born. From the orphaned son of a trader which received prophetic visions, he led his people against the superpowers of Rome and Ctesiphon, bringing with him a new religion, Islam.
However, unlike the violence and war-filled conquest of Middle Eurasia, Islam's entry into Nusantara was of a more mild nature. With the bulk of the muslim expansion focusing west towards Europe, its eastern peripheries see little to no conflict, embracing levels of prosperity never to be seen before by the Arab and Persian world. From this, traders flock and flourish as they path through the intersection of the Silk Road, bringing with them goods, gold, and the gospel of Muhammad with them, promising salvation and peace for those who follow.
Word of this new faith would soon travel far eastwards following the wind of trade, winding up in the Gujarati and Bengal coast, all the way to the far eastern trading ports of southern China by the 10th century. In here, the Muslim community would slowly but surely grow and flourish as they enjoy relatively high prosperity and stability, even as far as being employed by the Chinese emperors as delegates and envoys, with their silver tongue and eloquent speech a good suit in the realm of diplomacy.
In Nusantara, one of the earliest adopters of this new religion would be a king of an upstart kingdom. In the early 13th century, upon arrival of strange trading ships with triangulr sails come with them exotic goods and strange language, different of those Indian traders of old. Intrigued, he wished to learn further of the strange new faith they've came with, and from there, the king changed his name to Malik-ul Saleh, and converted to Islam, heralding the first Muslim state of the archielago, the Sultanate of Pasai.
It was not until the establishment of the Sultanate of Malacca that Islam in Nusantara would grow in substantial political power. Its king, Parameswaram, a former vassal of Majapahit has denounced the Hindu-kingdom rule, and set out to establish his own power base in the Malayan peninsula. Here, he would converse and rally the local populace, adopt the growing Muslim faith, and change his name to the Persianate name of Sri Iskandar Shah. He would utilize the muslim-diplomats of China to his advantage, most famously that from the voyage of Admiral Zheng He (Cheng Ho) of the Chinese treasure fleet to strike a protectorate deal with China, safeguarding them from further political intrusions from other neighbouring states.
From there on, Islam grew slowly but surely on the Archipelago, with new sultanates such as Demak, Banten, Mataram, and Cirebon rishing from the remnants of their old Majapahit and Hindu-Buddhist overlords. Ever expanding and encompassing nearly all of the present Indonesian state. Peasant da'wah from figures such as "Wali Songo" would also bring aflock many people into the faith as they travel far and wide into the Javan heartlands, spreading the word of Islam and Allah's guidance.
The arrival of the European colonizers would put an end to these Islamic Sultanates, slowly but surely being absorbed into their colonial influence stripped of all sovereignity and territory. Through dividing and conquering would they successfully brought down what the native's ancestors took centuries to build, in a means to "civilize" this corner of the world. However as it might be, the more liberal and secular governance of both the British and Dutch colonies would mostly leave the religious framework of said territories intact, leaving by the muslim faith mostly undisturbed all the way to their independence.
In the present day, nations such as Malaysia, Indonesia and Brunei can trace their culture, borders, and influence back to these old kingdoms, with the faith brought upon them not by conquest, but through careful diplomacy and trade, a slow but deepening exchange of culture from civilizations oceans apart from eachother. And in this, the mark can be felt on the aformentioned nation's policies, adopting a stance of active-neutrality and non-interventionism, as well as being closer to Middle Eastern and other Muslim countries of the world. And on the cultural level, the Muslim faith sees its integration into native architecture, art, literature, and even traditions, such as Halal Bihalal, Tumpengan, Sekaten and many others, which trace their origins to the Islamic syncretism brought about by the Sufist da'wah into Nusantara.