The Old Javanese calendar
The Old Javanese dating system, which was used to document the exact time when an event happened, consists of a number of elements. The elements used to document the date of Ken Angrok’s death consist of: a wara (the name of the day), a wuku (the name of the week), and a warsha (the year).
A wara is a solar day; there are various types of wara names. The names of the days of the 7-day week (saptawara) are: Aditya, Soma, Anggara, Budha, Wrehaspati, Sukra and Saneshcara. This 7-day week is comparable to our 7-day week. There is also a 6-day week (sadwara), consisting of the days Tunglai, Hariyang, Wurukung, Paniruan, Was and Mawulu. Finally, there is a 5-day week (pancawara), consisting of the days Pahing, Pon, Wagai, Kaliwuan and Umanis.
The combination of saptawara, sadwara and pancawara results in a 210-day cycle. In the 210-day cycle, Tu Pa A (Tunglai Pahing Aditya) is the first day, while Ma U Sa (Mawulu Umanis Saneshcara) is the last day. The combination of sadwara, pancawara and saptawara, which forms a year of 210 days, is divided into 30 wuku (weeks) of seven days that form combinations of the days of the three types of weeks.
The thirty wuku have names. They are: Sinta, Landep, Wukir, Kurantil, Tolu, Gumbreg, Wariga ning Wariga, Wariga, Julung Wangi, Sungsang, Kuningan, Langkir, Madasiha, Julung Pujut, Pahang, Kuruwlut, Marakih, Tambir, Madangkungan, Mahatal, Wuyai, Manahil, Prangbakat, Bala, Wugu, Wayang, Kulawu, Dukut and Watu Gunung.
In this system Landep is the second wuku or week. It consists of seven days, namely Ha Wa A, Wu Ka So, Pa U Ang, Wa Pa Bu, Ma Po Wr, Tu Wa Su and Ha Ka Sa. For the date of Ken Angrok’s death the Pararaton only mentions the pancawara day (Pon) and the saptawara day (Wrehaspati), which means that the sadwara day was Mawulu. In the order of the wuku system this would be: Mawulu Pon Wrehaspati (Ma Po Wr), which is the twelfth day of the 210-day cycle.
Date of Ken Agrok's death
In his work Études d’Épigraphie Indonésienne IV (1955), Louis-Charles Damais composed a table of the 210-day cycle and the wuku based on the Julian calendar, beginning with the first day, Tu Pa A (Tunglai Pahing Aditya).
Ken Angrok’s death, in Shaka 1149, could, on the basis of the wuku system, be construed to be on 17 January 1227, 15 August 1227 or 12 March 1228.
The first date, 17 January 1227, cannot be right because this falls in the previous Shaka year (1148). The third date, 12 March 1228, also cannot be correct because it would be in the following Shaka year (1150). Thus, the first day of Tu Pa A in the Shaka year 1149 falls on 15 August 1227. Ma Po Wṛ is the 12th day of the Landep wuku, the second week, in the 210-day cycle.
Therefore, Ken Angrok’s death occurred on 26 August 1227. It is further specified that it was at sunset (around 5.30 pm). If one converts this to the Old Javanese calendar, the complete date is: Shaka 1149, bhadrawada masha (Karo), tithi trayodaśi shuklapaksha, ma po wr wara, landep.