Cicero, Marcus Tullius

Nomina sunt odiosa (naming names is tricky)

Omnia praeclara rara (Everything excellent is rare)

Omnia rerum principia parva sunt (The origin of all things is small)

Salus populi suprema lex esto (The welfare of the people shall be the supreme law)

Silent leges inter arma (The laws are silent in war)

Somnus imago mortis (Sleep is the image of death)

Summum ius summa iniuria (The greatest right is the greatest wrong)

Suum cuique (To each his own) (Also: Words above the entrance gate of the Buchenwald concentration camp) (In 1998 Nokia stopped an advertising campaign headlined with the words "To each his own")

Ut sementem feceris, ita metes (As you sow, so shall you reap)