Menalkidas had been charged by Kallikrates of Leontion with a capital offence, but saved himself by gaining the support of Diaios, whom he bribed with three talents.
Diaios was generally blamed for this and, trying to divert public attention away from his own conduct, he sought a quarrel with Lakedaimon.
In response, the Roman senate had said that decisions on all causes, except those of life and death, rested with the great council of the Achaians.
In truth, the Senate had made no final decision, but had promised to send commissioners to settle the dispute.
However, Diaios, who was again general of the Achaean league in 147 BC, did seek to obey Rome's prohibition by endeavouring to bring over the towns around Sparta by negotiation.
When the decree of the Romans arrived (see Achaean War), which severed Sparta and several other states from the Achaian league, Diaios took a leading part in building Achaian indignation and in urging them to the acts of violence which caused war with Rome.
(This outcome was based on the law of the Achaians, which provided in such cases that the predecessor of the deceased should resume his authority.)
Diaios then had Sosikrates, the lieutenant-general, as well as Philinos of Korinth, tortured to death for having recommended negotiation with the Romans.