The story of the mosque begins not in Kalimantan but in Semarang, on the north coast of Java. In 1733, a Muslim scholar named al Habib Hussein arrived in West Kalimantan, where the Sultan of Matan, Kamaluddin, received him and appointed him Mufti of Religious Matters. Hussein married the sultan's daughter, Nyai Tua, and from this union Syarif Abdurrahman Alkadrie was born. When a falling-out between Hussein and Sultan Kamaluddin drove the family to the neighboring Mempawah Kingdom, young Alkadrie inherited his father's religious authority after Hussein's death. But Alkadrie had grander ambitions than serving another ruler's court. He assembled an entourage of fourteen boats and set out downstream on the Kapuas River, seeking a place to establish his own Muslim sultanate.

The spot Alkadrie chose was strategic: the confluence of the Kapuas River and the Landak River, a natural crossroads for trade and travel in the vast interior of Borneo. His followers cleared the forest near the estuary and began construction of both a kraton -- a royal palace -- and a mosque. The original mosque was a humble affair, small and wooden with thatched roofing, but it represented something profound: the establishment of Islamic worship at the heart of a new political order. Alkadrie proclaimed the Pontianak Sultanate, and the mosque became its spiritual center, standing alongside the Kraton Kadriyah as one of the city's founding structures. For the next thirty-seven years, until his death in 1808, Alkadrie ruled from this riverside seat of power.

When Alkadrie died, his son Sharif Usman was still a child. The sultanate passed instead to Alkadrie's brother, Sharif Kasim, who held the throne until Usman came of age. Usman succeeded his uncle and ruled from 1819 to 1855, and during his reign he undertook the mosque's most significant transformation. In the month of Muharram, 1827, Usman rebuilt the mosque and named it Abdurrahman Mosque in honor of his father -- a gesture that tied the building's identity permanently to its founder. The rebuilt structure followed the architectural traditions of Indonesian mosques, centered on six saka guru, the great main posts that support the multi-tiered roof. These posts were carved from belian wood, the legendary ironwood of Borneo, a timber so dense it sinks in water and so durable that structures built from it can stand for centuries.

Belian wood, known scientifically as Eusideroxylon zwageri, is native to the rainforests of Kalimantan and has long been prized across the Indonesian archipelago for its extraordinary hardness and resistance to rot. Building an entire mosque framework from this material was both a practical choice -- ensuring the structure would endure the tropical climate -- and a statement of permanence. The multi-tiered roof, a hallmark of mosque architecture across Java and Kalimantan, rises in stepped layers above the prayer hall, each tier lifting the eye upward. This layered design traces its roots to pre-Islamic Javanese architecture, adapted over centuries to serve the needs of Muslim worship. At the Jami Mosque, the six ironwood pillars anchor everything, carrying the weight of the roof and the continuity of a tradition that stretches back to the sultanate's founding.

Today, the Jami Mosque of Pontianak -- also known as the Sultan Syarif Abdurrahman Mosque -- remains the oldest mosque in the city. It sits in Dalam Bugis Village in East Pontianak, near the Kadriyah Palace, much as it has since 1771. The city that grew around these twin landmarks now sprawls across the equatorial lowlands of West Kalimantan, a bustling provincial capital of several hundred thousand people. But the mosque still occupies its original role at the spiritual heart of Pontianak, a living reminder that the city began with fourteen boats, a cleared patch of jungle, and a scholar's son who believed he could build something lasting where three rivers met.