Final answer:
The original Roman calendar attributed to Romulus had 10 months. It was not aligned with the lunar or solar years, leading to later reforms that established the 12-month Julian calendar.
Step-by-step explanation:
The calendar attributed to Romulus, the legendary first king of Rome, originally consisted of 10 months. This early Roman calendar did not align neatly with the seasons as it was not based on the lunar or solar year, making it difficult to maintain over time. Later, the Roman calendar was reformed to include 12 months, which better corresponded to the solar year, a structure that was formalized with the introduction of the Julian calendar by Julius Caesar in 46 BC.