I heard Mozart's dad wrote the melody. This is the version I grew up with in Ireland.

Sleep little prince and lie still
folded the sheep on the hill
silent the hum of the bees
birds are at rest in the trees
quiet and peaceful the room
slowly the big silver moon
rises and peeps o'er the sill
sleep little prince and lie still
lie still, lie still (very slowly)

not even a mouse is a stir
cupboard and cellar are bare
calm lies o'er palace and park
never a sound in the dark
save for the maiden who cries
wakes from her slumber and sighs
dreaming as fond lovers will
sleep little prince and lie still
lie atill....lie still

None is so happy as thou
free as a bird on the bough
plenty of nice things to eat
fine golden shoes for thy feet
carriage and horses to ride
footmen to run by thy side
all will be thine if thou wilt
sleep little prince and lie still,
lie still lie still