He is also said to have made much use of the Greek historian Diodes of Peparethus.
Diodes appears also as the author of a code of laws of great strictness, which was held in such esteem that later lawgivers were deemed only its expounders.
He went back to Sicily, warred with Carthage on his own account, and brought back the bones of the unburied Syracusans from Himera, but was still so dreaded that the people banished Diodes without restoring him.
Thus Nicomedes invented the conchoid; Diodes the cissoid; Dinostratus studied the quadratrix invented by Hippias; all these curves furnished solutions, as is also the case with the trisectrix, a special form of Pascal's limacon.
The term cissoid has been given in modern times to curves generated in similar manner from other figures than the circle, and the form described above is distinguished as the cissoid of Diodes.