Complex sentence: Thiruvanchikulam in Kodungallur was the capital of the second Chera dynasty up to the 12th century AD, after the Cheras, Thiruvanchikulam was ruled by Kingdom of Cochin (Perumpadapu Swaroopam).
Split into simpler sentences: Thiruvanchikulam in Kodungallur was the capital of the second Chera dynasty up to the 12th century AD. After the Cheras, Thiruvanchikulam was ruled by Kingdom of Cochin (Perumpadapu Swaroopam).