Bakara Archive is written heritage of Kingdom Sisingamangaraja in Bakara, contains about:
1. History of Batak Kingdom up to Sisingamangaraja as King.
2. Batak rejection of Si Bontar Mata (Batak call the Dutch as Si Bontar Mata, means the white eyes)
3. An official reports and government documents of Sisingamangaraja XI in detail, completely and accurately the events along the year.
4. The Work Plan to rebuild and reconstruction the land of Bakara after war.
Bakara Archive is hand written using Batak script and language, wrote use qualified waterproof Chinese ink on foolscap size paper made in Italy. All the material sent to Bakara through over Aceh. Batak script and language which was the archive of Sisingamangaraja XI.
There are 23 volumes, each + 5cm thick. Every books covered with buffalo leather and cotton. Very neat, like a row set of Encyclopedia Book. The thickness of all the book around 1.5m.
The Archice rescued by Reverend Pilgram in 1884, then saved by Joustra and subsequently handed over Poortman in Voorburg Holland.