From The Art of Courtly Love by Andreas Capellanus
Thou shalt avoid avarice like the deadly pestilence and
shalt embrace its opposite.
Thou shalt keep thyself chaste for the sake of her whom thou lovest.
Thou shalt not knowingly strive to break up a correct love affair
that someone else is engaged in.
Thou shalt not chose for thy love anyone whom a natural sense
of shame forbids thee to marry.
Be mindful completely to avoid falsehood.
Thou shalt not have many who know of thy love affair.
Being obedient in all things to the commands of ladies, thou shalt
ever strive to ally thyself to the service of Love.
In giving and receiving love's solaces let modesty be ever present.
Thou shalt speak no evil.
Thou shalt not be a revealer of love affairs.
Thou shalt be in all things polite and courteous.
In practising the solaces of love thou shalt not exceed the desires of thy lover.