It awakened general interest in the different arts as medium of expression
The last one should be the correct one
The kingdom went into decline from the mid-16th century CE when the Portuguese, put off by the interference of Kongo's regulations on trade, moved their interests further south to the region of Ndongo. The latter kingdom had already defeated a Kongo army in 1556 CE.
The answer to the first question is: the king of India, he never conquered India. The answer to the second: Phalanxes. The phalanxes were based on the usage of long spears, that would stop the enemy advancing.