The Báb, the founder of the Bábí Faith, instituted the Badí‘ calendar in the Persian Bayán with 19 months of 19 days each and a period of intercalary days to allow for the calendar to be solar. The introduction of intercalation marked an important break from Islam, as under the Islamic calendar the practice of intercalation had been specifically prohibited in the Qur'an.[5] The Báb did not, however, specify where the intercalary days should go.[5] Bahá'u'lláh, who claimed to be the one foretold by the Báb, confirmed and adopted the Badi calendar in the Kitáb-i-Aqdas, his book of laws.[5] He placed the intercalary days before the fasting month of `Alá, the nineteenth and last month,[6] and gave the intercalary days the name "Ayyám-i-Há" or "Days of Ha".[5][6] Prior to 172 B.E. (2015 A.D.), Ayyám-i-Há was from sunset on February 25 to sunset on March 1.[7]