Conversation so far:
How were the Sinhalese kingdoms formed?
Tambapanni.
Who or what are the Tambapanni?
landed on the island at a site believed to be in the district of Chilaw, near modern-day Mannar, and founded the Kingdom of Tambapanni.
Is this were the Sinhalese live today?
after the death of Vijaya and the end of the Kingdom of Tambapanni.

Question: Who is Vijaya?
Self-contained rewrite: Who is Vijaya to the Sinhalese people?