Fort Willem I, Ambarawa

During the Diponegoro War (1827-1830), Colonel Hoorn, Commander of the 2nd Division, assigned to the crossroads at Bawen, instructed the construction of a logistical supply point, as well several military barracks, to give immediate supply and forces for the war, as Bawen is a vital junction connecting the cities of Semarang, Yogyakarta, Salatiga and Surakarta. As a result, several sheds, made out of bamboo, were built at this strategic point during the war.{{sfn|Mahandis Yoanata|2009}}

After the war, during the reign of Willem II, a fort was constructed in Ambarawa between 1834 and 1853. In 1840, Ambarawa had become a strategic military outpost, serving as a choke point between Semarang and Surakarta. The Dutch had also established several military defense points along this route. Their purpose was to establish a relationship with the Sultanate of Mataram and to prevent native troop movements.{{sfn|Mahandis Yoanata|2009}}

From 1853 to 1927 KNIL military barracks were set up in the fort. The private Dutch East Indies Railway Company (NIS) received concession in 1862 to build a rail track connecting Semarang, Surakarta, Magelang and Yogyakarta with a branch toward Fort Willem I.{{sfn|M. Sahari Besari|2008|p=136}} Construction started in 1863 and was completed in 1873.{{sfn|M. Sahari Besari|2008|p=136}} An earthquake occurring on July 16, 1865, damaged some buildings inside the fort.{{sfn|Mahandis Yoanata|2009}} In 1927, Fort Willem I changed its function from a juvenile penitentiary into an adult and political prison.{{sfn|Mahandis Yoanata|2009}}

During the period of Japanese occupation, Fort Willem I was converted into an internment camp.{{sfn|Mahandis Yoanata|2009}}

After the Indonesian declaration of independence, from October 14, 1945, to November 23, 1945, parts of the fort were also used as a military base by the Tentara Keamanan Rakjat ("People's Security Army"), a predecessor of the Indonesian National Army. During which time, around 3,500 Dutch civilians were interned by Indonesian freedom fighters inside the Fort Willem I; the internment camp used former prisoners and guards for camp security.{{sfn|Mahandis Yoanata|2009}}

In 1950, parts of the fort were converted into an adult penitentiary. In 1985, it was repurposed yet again as a juvenile penitentiary facility; in 1991, penitentiary class IIB; in 2003 and until now, penitentiary class IIA.{{sfn|Mahandis Yoanata|2009}}

Fort Willem I is situated in the middle of a rice field. The main building is a pentagonal fort, sized around 178 x 178 meter. Small storage buildings are located around 94 meter away from the fort at each cardinal points.

Unlike earlier 18th-century fort designs, the 19th-century Willem I Fort were designed for a mainly defensive and logistical purpose. As such, the fort contains no embrasures or bastions. Instead, there are many windows in the rampart, and the bastions are detached from the fort.{{sfn|Mahandis Yoanata|2009}}

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• {{cite book |author=M. Sahari Besari |editor=Reza Anggara |date=2008 |title=Teknologi di Nusantara: 40 abad hambatan inovasi |trans-title=Technology in Nusantara: 40 centuries of obstacles in innovation |url=https://books.google.com/books?id=8ByjqGxHDRkC&dq=%22willem+I%22+fort+ambarawa&pg=PA136 |language=Indonesian |location=Jakarta |publisher=Penerbit Salemba Teknika |isbn=9789799549259}}
• {{cite web |url=http://mahandisyoanata.blogspot.co.id/2009/10/inside-fort-willem-i-at-ambarawa.html |title=INSIDE FORT WILLEM I AT AMBARAWA |author=Mahandis Yoanata |date=October 12, 2009 |website=My Odyssey |publisher=Blogspot |access-date=November 28, 2015 |archive-url=https://web.archive.org/web/20151128065730/http://mahandisyoanata.blogspot.co.id/2009/10/inside-fort-willem-i-at-ambarawa.html |archive-date=November 28, 2015 |quote=}}

{{refend}}

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Category:Dutch colonial architecture in Indonesia

Category:Installations of the Royal Netherlands East Indies Army

Willem I

Category:Semarang Regency

Category:Buildings and structures completed in 1845