Final answer:
The three kingdoms of the Kathmandu Valley before its unification were Kantipur, Lalitpur (Patan), and Bhaktapur, each contributing to the cultural heritage of the region.
Step-by-step explanation:
Before the unification of Nepal, the Kathmandu Valley was ruled by three distinct kingdoms. These were:
Kantipur, corresponding to modern-day Kathmandu - it was one of the major kingdoms in the valley and later became the capital of the unified Nepal. It has been a significant cultural and trade center for centuries.
Lalitpur (Patan), located in the current Lalitpur Metropolitan City
Bhaktapur, situated in today's Bhaktapur District
These kingdoms were influential in the Kathmandu Valley region and contributed significantly to its rich cultural and architectural heritage, evident in the numerous temples and palaces that still stand today.