Now from a Copper Plate Grant that remained among the Christians of Kollam in Kerala State we note the following text..

“…..After the royal punishment implemented against 72 - families of Vellalar of Kaviripoompattinam who believed and joined the Christian faith, they boarded a ship and went to the the place
Kurakkeni (Kollam) where the (other) Kurakkeni Christians too lived like relations in the year A.D.293. The Christians from Niranam too (north of Kollam) came to Kurakkeni and saw the Tamils there and followed few Tamil customs and Malayalam customs and lived there.

(During this time) the one who performed miracles (and) by the name Maanikkavaasakar met the Christians who came newly to this region, by his miracles set the God he worshiped on them and caused fever, faintishness, and crippling of limbs, and killing the (domestic) animals and those who became sick thus when they humbly meet him and receive holy ash (thiruneeru) and on applying they get cured (of sickness )and rid off evil spirits.
The Copper Plates belong to 9th Century and written in Vatteluththu. So Quoting that would not help.

The Linguistic use of Tamil word and Etymology shall not support Manickavasagar to 3rd Century, the Kings referred all belong to 2nd Pandya/Chola Period.