The Nile's annual floods influenced the development of which Egyptian timekeeping system?

• A. A lunar calendar
• B. A solar calendar synchronized to the flood cycle
• C. A lunisolar calendar
• D. A religious calendar

Answer: (B)

Egyptians needed a time system that reliably matched the river’s predictable yearly pattern so they could plan irrigation, planting, and harvesting after the Nile’s floodwaters receded. They developed a solar calendar for civil use, consisting of 365 days with 12 months of 30 days plus five extra days, divided into seasons that reflect the river’s behavior: the flood season, the growing season, and the harvest season. This solar framework stayed in step with the annual cycle, making administration and agricultural work consistent from year to year.

The flooding’s regular rhythm is what drives this answer. A lunar calendar would drift relative to the solar year because it tracks lunar phases, and a lunisolar calendar tries to reconcile both but Egypt’s primary administrative timekeeping relied on the solar year. A religious calendar exists in ancient Egyptian practice, but the specific system aligned with the Nile’s floods for everyday farming and governance is the solar calendar synchronized to the flood cycle.