The Brantas is the longest river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in East Java

East Java

East Java is a province of Indonesia. It is located on the eastern part of the island of Java and includes neighboring Madura and islands to its east and to its north East Java is a province of Indonesia. It is located on the eastern part of the island of Java and includes neighboring Madura and...

. It drains an area over 11,000km² from the southern slope of Mount Kawi

Mount Kawi

Mount Kawi or Gunung Kawi is a stratovolcano in East Java on Java island, Indonesia. It is a massive volcano, adjacent to Mount Butak. There is no historical record of its eruptions....

-Kelud-Butak, Mount Wilis

Mount Wilis

Mount Wilis is a solitary volcanic massif surrounded by low-elevation plains. It is located in Java island, Indonesia. No confirmed historical eruptions are known from this volcano....

, and the northern slopes of Mount Liman-Limas, Mount Welirang, and Mount Anjasmoro. Its course is semi-circular or spiral in shape: at its source the river heads southeast, but gradually curves south, then southwest, then west, then north, and finally it flows generally eastward at the point where it empties into the Java Sea.

History

King Mpu Sindok

Mpu Sindok

Mpu Sindok, throne name: Sri Isyana Vikramadhammatunggadeva, was the last king of the Sanjaya Dynasty who ruled the Kingdom of Mataram from Central Java, reigned from around 928 or 929 AD. Mpu Sindok moved the seat of power of the Mataram kingdom from Central Java to East Java in 929 AD, probably...

 moved his kingdom from Mataram Kingdom

Mataram Kingdom

The Medang or Mataram Kingdom was a Hindu-Buddhist kingdom that flourished between the 8th and 10th centuries CE. It was based in Central Java, and later in East Java. Established by King Sanjaya, the founder of the Sanjaya dynasty, the kingdom was ruled by the Sailendra and Sanjaya families...

 in Central Java

Central Java

Central Java is a province of Indonesia. The administrative capital is Semarang. It is one of six provinces on the island of Java.This province is the province of high Human Development in Indonesia and its Points Development Index countries is equivalent to Lebanon. The province of Central Java...

 to a new location on this river at circa 950 A.D. Possibly (only one of a number of reasons given) due to a Mount Merapi

Mount Merapi

Mount Merapi, Gunung Merapi , is an active stratovolcano located on the border between Central Java and Yogyakarta, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548...

 volcanic eruption, he had to leave his kingdom to this new safe place near present city of Madiun

Madiun

Madiun is a city in the western part of the province of East Java Indonesia, an agricultural centre. It is the capital of the regency of the same name....

.