Final answer:
The first month of the Muslim calendar is Muharram, marking the start of the lunar Hijri year and being one of the sacred months in Islam.
Step-by-step explanation:
The first month of the Muslim calendar is Muharram. This month is significant in Islamic culture as it marks the beginning of the lunar Hijri year. Muharram - a day of immense importance for Muslims - commemorates the death of the Prophet Muhammed's grandson, Hussein Ibn Ali. Muharram is also a time of remembrance for the Muslim Ummah. The Hijri calendar is based on the lunar cycle, which is different from the solar Gregorian calendar that is commonly used in the Western world. Muharram is considered one of the four sacred months in Islam, during which warfare is traditionally forbidden. It is a time of reflection and peace.