Sestertius, a Roman coin either bronze or silver one-fourth of a denarius, originally worth 2½ asses but afterwards 4 asses, up to the time of Augustus was worth fully 2d., and subsequently one-eighth less; Sestertium, a Roman “money of account,” never a coin, equalled 1000 sestertii, and was valued at £8, 15s.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Sesostris * Settle, Elkanah