Later his son Tipu sultan became the ruler .
In 1757 , to check the invasion of the Zamorin of Calicut , the Palakkad Raja sought the help of Hyder Ali of Mysore .
Later Palakkad Raja 's son Tipu sultan became the ruler .
In 1757 , to check the invasion of the Zamorin of Calicut , the Palakkad Raja sought the help of Hyder Ali of Mysore .