Kilwa Kisiwani, also known as Kilwa Island, is an island, historic site, and small community located in the township of Kilwa Masoko. It is the main town of Kilwa District in Lindi Region, southern Tanzania. Kilwa Kisiwani is the largest of nine hamlets in Kilwa Masoko and has the fewest people among them, with about 1,150 residents.

Historically, Kilwa Kisiwani was the center of the Kilwa Sultanate, a medieval Swahili kingdom that ruled much of the Swahili Coast during the 13th, 14th, and 15th centuries. At its height in the Middle Ages, Kilwa had more than 10,000 people. Since 1981, the entire island of Kilwa Kisiwani has been recognized by UNESCO as a World Heritage Site, along with the nearby ruins of Songo Mnara. Kilwa Kisiwani is also a National Historic Site of Tanzania. In addition, it is one of seven World Heritage Sites in Tanzania. The island remains home to a small community of people who have lived there for many years.

Geography

Kilwa Kisiwani Island is located 9 degrees south of the equator. The island has a circumference of 23 km (14 mi), and its total land area measures 12 km² (4.6 sq mi). The western part of the island features the Mavuji River estuary. The southern part of the island includes the Sagarungu sound, and the Indian Ocean is located to the east.

Economy

The island is part of the Kilwa Masoko township authority. The main activities that provide income on the island include cultural tourism, fishing, and growing crops for personal use. Economic growth is limited because the island is far from other areas. There are no rivers, and the main source of water is wells. Many of the island's freshwater wells have been used for more than 1,000 years. Small boats connect the island to Kilwa Masoko. The only electricity on the island comes from solar power, but it has limited capacity. There are no roads on the island, so most movement is done on foot or by motorcycle.

To keep the island's history safe, people who live outside the island are not allowed to visit without a permit from the tourist information center in downtown Kilwa Masoko. Many historical items and buildings on the island have not yet been studied or uncovered.

Historical significance

Kilwa Kisiwani is a former Swahili city located on the Swahili Coast, part of the Kilwa Archipelago. Excavations and Carbon-14 dating show that the city was founded at the beginning of the 9th century CE. Like other areas on the East African coast, trade on the island was affected by seasonal wind patterns.

In 1331 CE, a Moroccan traveler named Ibn Battuta visited Kilwa and described it as one of the most beautiful cities in the world. Trade with the Arabian Peninsula, India, and China helped Kilwa grow. Though Islamic traditions and words influenced the culture, the city’s origins are African. Many Swahili settlements had complex layouts that showed social relationships. However, after the Portuguese Empire burned the city in July 1505, many questions remain about its layout.

Swahili cemeteries were located on the edge of the town, which is common in the Swahili region. Large open spaces were likely used for social gatherings. Kilwa was an important trading city, and by the 13th century, it had stronger fortifications and more goods moving through it. A political system was needed to manage trade and people. Much of Kilwa’s trade was with the Arabian Peninsula. Kilwa reached its peak in wealth and commerce between the 13th and 15th centuries.

Evidence of wealth includes the appearance of stone buildings around the 13th century, replacing earlier wattle-and-daub structures. The type of house someone lived in suggested their social and economic status. Kilwa exported spices, tortoiseshell, coconut oil, ivory, and aromatic gums, as well as gold. Around this time, Kilwa controlled the gold trade at Sofala, Mozambique. Wealthier residents owned exotic textiles and foreign ceramics, though luxury items are not preserved in the archaeological record. Kilwa minted its own coins from about 1100 to 1600 CE, and these coins have been found in places like Great Zimbabwe.

Marine resources provided food, and land produce was used to supplement it. The poor quality of soil covering the limestone at Kilwa meant that food came from higher ground. However, the soil in the Kilwa region was good for growing cotton, used in sail-making. Spindle whorls from the 12th century show that cotton was processed there.

Early studies focused on Kilwa’s ports and harbors, but more attention is now given to the hinterlands. Ceramics found at the site are divided into two groups: regional and coastal. Regional ceramics were locally made but had limited distribution. These unglazed ceramics, called Kitchen Wares, were not only used for cooking. Locally made pottery found in the region was also found at Kilwa itself.

Kitchen Wares were common throughout the region, but other ceramics were mostly found at Kilwa. These included modeled forms and red-burnished wares, which were distributed along the coast. Imported ceramics from the Arabian Peninsula and China were found only in Kilwa and were used by the elite to show social status. These items were displayed in wall niches and held symbolic importance in Swahili culture. The lack of imported goods in the hinterlands suggests that other local communities did not undergo the same level of change as Kilwa.

A study by Brielle et al. in 2023 analyzed ancient DNA from 80 individuals from six medieval and early modern coastal towns and an inland town. The study aimed to determine the proportions of "African-like, Persian-like, and Indian-like" DNA. More than half of the DNA from coastal towns came from African ancestors, with a large portion from Asian ancestors, including Persian men. African and Asian origins began mixing around 1000 CE. Samples were taken from human remains excavated in the 1950s and 1960s by Chittick.

After 1500 CE, male Asian DNA became increasingly Arabian, showing more interaction with southern Arabia. Over time, interactions with different Asian and African groups changed the ancestry of modern Swahili people compared to medieval individuals.

Analysis of DNA from individuals potentially dating to 1300–1600 CE showed a L* haplotype in mitochondrial DNA, common in Sub-Saharan Africa. Y chromosome analysis showed the J2 haplotype, found in Southwest Asian or Persian individuals. X chromosomes showed more African ancestry compared to autosomal DNA, supporting evidence of African maternal and Persian or Southeast Asian paternal ancestry.

In 2004, Kilwa Kisiwani was added to UNESCO’s List of World Heritage in Danger due to rapid damage from erosion and vegetation. The eastern part of the Palace of Husuni Kubwa is disappearing, and rainwater erosion threatens remaining structures. Vegetation on cliffs limits erosion but damages masonry. Volunteers from CHAM protected the site between 2001 and 2007.

The World Monuments Fund listed Kilwa on its 2008 Watch List of 100 Most Endangered Sites and supported conservation efforts. Kilwa was removed from the list in 2014.

Historic buildings

The earliest section, likely the northern prayer hall, was built in the 12th century. According to historical records, this rectangular structure was built between 1131 and 1170. The walls were made of square coral limestone blocks, and three symmetrical entrances with vaulted ceilings allowed people to enter. Unlike other mosques in the area, the flat roof was supported by nine hexagonal columns made from single tree trunks.

Archaeological discoveries have revealed details about the original design. The roof was made of coral tiles held together with mortar and had decorative concentric circles. Traces of red paint suggest the mosque may have been decorated in red and black.

In the early 14th century, Sultan al-Hasan ibn Sulaiman expanded the mosque. He also built the nearby palace of Husuni Kubwa. This expansion likely included the grand dome described by Ibn Battuta during his visit in 1331.

The mihrab, the niche that shows the direction of prayer, was added later. Its design—featuring a pointed arch, capitals, pilasters, friezes, and a fluted half-dome vault—differs from the original structure. Protruding coral blocks suggest a fixed wooden minbar was once present, and traces of oblong niches within the main niche hint at a possible Shirazi influence. These elements may have been added during renovations.

The western section of the mosque housed the ablution area, where worshippers performed ritual cleansing before prayers. Restoration efforts uncovered an intricate network of water channels made from baked clay, showing how the mosque managed water effectively.

Husuni Kubwa, the "Great Palace," was built outside the town in the early 14th century. It was a sultan’s palace and trading center. Other features include causeways and platforms at the harbor entrance made from reef and coral blocks nearly a meter high. These structures act as breakwaters, allowing mangroves to grow, which helps identify them from a distance. Some causeways were built from bedrock, which was used as a base, while coral stone was added with sand and lime to hold the stones together. Some stones were left loose.

The Palace of Husuni Kubwa is a major structure in Kilwa. Most of it was built in the 14th century by Sultan al-Hasan ibn Sulaiman, who also expanded the nearby Great Mosque of Kilwa. Some parts may date back to the 13th century. For unknown reasons, the palace was only inhabited briefly and was abandoned before completion.

Built in true Swahili architectural style, the palace was constructed from coral stone on a high bluff overlooking the Indian Ocean. It has three main parts: a south court for trade, a residential area with over 100 rooms, and a wide stairway leading to a beachside mosque.

Other features include a pavilion, likely used for receiving guests, and an octagonal swimming pool. The entire palace covers about two acres. Coral rag was set in limestone mortar, and cut stone was used for decorative elements, door frames, and vaults. The rooms were about 3 meters tall. The roof was made of cut limestone blocks placed over cut timbers, and the floors were covered in white plaster. The main entrance to Husuni Kubwa is from the shore.

Most of the imported pottery found at the site was Chinese celadon, though a few pieces of Ying Ch'ing stoneware and a Yuan dynasty flask dated to about 1300 CE were also discovered. Neither the Kilwa Chronicle nor Portuguese accounts describe a building similar to Husuni Kubwa.

Husuni Ndogo, or "Little Palace," was built from coral rubble and limestone mortar. A rectangular wall surrounds the complex, with towers at each corner. The foundations extend two meters below ground level. It appears to have been built as a fort, though its exact purpose is unclear. Some evidence suggests it may have been used as a mosque at times. Its design resembles buildings from the Umayyad Caliphate (661–750 CE), but it is uncertain whether it is related to those structures or dates to the same period.

The Gereza Fort, also called the Arab Fort, is located between the Makutani Palace and the Great Mosque. Evidence suggests the original structure was Portuguese, while the current form is typical of Omani forts. The word "Gereza" means "prison" in Swahili, which may indicate the fort was used as a slaveholding site by Omanis during the late 18th to late 19th centuries, after the collapse of the Swahili civilization following the arrival of the Portuguese in the late 16th century.

Controversies

Much of Kilwa's history was recorded by Omani and European colonial leaders in the 19th century. Some evidence about Kilwa's past and the role of people from other countries is conflicting.

According to local stories passed down through generations, the island of Kilwa Kisiwani was given to Ali bin Hasan in the 11th century. He was the son of a ruler from Shiraz, a city in Persia. Another story says Ali’s mother was from Somalia. Ali bin Hasan is believed to have started the city on the island and married the daughter of a local king. Even though he is credited with founding the city, it was already inhabited when he arrived. He later became powerful and strengthened the city’s defenses and trade. It is also said that the child of Ali and the local king’s daughter started the Kilwa Sultanate.

Archaeological and written records show that over time, Kilwa became a major city and the most important trading center on the southern part of the Swahili Coast, which includes areas from the Tanzania-Kenya border to the mouth of the Zambezi River. Kilwa traded gold, iron, ivory, and other goods from the African interior for items like beads, cloth, jewelry, porcelain, and spices from Asia. However, there is no evidence that the Shia Islamic traditions from Shiraz were present in Kilwa or along the East African coast.

By the 12th century, under the Abul-Mawahib dynasty, Kilwa became the strongest city on the Swahili Coast. At its peak in the 15th century, the Kilwa Sultanate ruled over many cities and islands, including Malindi, Mombasa, Pemba, Zanzibar, Mafia, Comoro, Sofala, and trading posts on Madagascar.

In 1331, the traveler Ibn Battuta visited Kilwa and praised the kindness, humility, and religious practices of its ruler, Sultan al-Hasan ibn Sulaiman. He also noted that the sultan led raids into the interior to capture slaves and other goods. Ibn Battuta admired the city’s well-planned layout, which he believed helped Kilwa thrive. During this time, the Palace of Husuni Kubwa and a large expansion of the Great Mosque of Kilwa were built using coral stone. The mosque was the largest of its kind. Kilwa was a wealthy city due to trade, and some people lived comfortably with indoor plumbing in stone homes, while others lived in poor conditions in mud houses with thatched roofs.

In the early 16th century, Portuguese explorer Vasco da Gama forced Kilwa’s wealthy Islamic rulers to pay tribute. In 1505, another Portuguese force led by D. Francisco de Almeida captured the island after a siege. Portugal controlled Kilwa until 1512, when an Arab mercenary took it back after the Portuguese left. Kilwa recovered some wealth but was conquered by Omani rulers from Zanzibar in 1784. In 1776, Kilwa’s ruler signed an agreement with a French merchant to supply 1,000 slaves each year. After the Omani takeover, the French built a fort on the island’s northern tip, but the city was abandoned by the 1840s. From 1886 to 1918, Kilwa was part of the German East Africa colony.

Health and education

The island currently has a population of just over 1,000 people. There is one primary school on the island called the Lyahi Koranic Middle School. Students who are older must travel to the mainland to continue their education. There are no healthcare facilities on the island, so residents must take a boat to the mainland to receive medical care. They can visit either the Masoka Urban Health Center or the Masoko BAKWATA Dispensary, both located in Kilwa Masoko.