Final answer:
The event occurred in 1045 BC as established by correlating astronomical events with Zhou royal chronology.
Step-by-step explanation:
The event in question occurred in the year 1045 BC. This was determined through the coordination of astronomical events with the relative royal chronology of the Zhou kings following excavations in 1976, which revealed inscriptions on Zhou bronze vessels. This chronological framework was notably reinforced by astronomer David Nivison's findings and the recording of a syzygy in the 41st year of King Wen's reign, indicating a lineup of the five visible planets.