Correct me if I am wrong, but I do believe Singapore was ruled
by Thailand in 1400 AD.
When the Indon prince Parameswara fled here in 1400, he murdered
the Thai chief. As a result, the Thais sent an expeditionary force
to Singapore. Parameswara fled to Malacca where he founded the
Malay kingdom.
Not exactly, but nice try anyway.
1stly, it was Ayutthaya, a southern-based kingdown (power rival
Chiangmai ruled the north). Ayutthaya was destroyed by the Burmese
in the 16th C; modern-day Thailand, inc. their present royal
family, traced their direct lineage from those who drove out those
conquerors.
2ndly, the Siamese claimed suzerainty, rather than overt
sovereignity, over S'pore.
3rdly, it's not like S'pore presently only has a few Bugis &
Orang Laut sea gypsies defending ourselves.