<P> Yet another theory is that the song is based around a 17th century ritual that took place after a newborn baby had died . The mothers would hang the child from a basket on a branch in a tree and waited to see if they would come back to life . The line "when the bough breaks the baby will fall" would suggest that the baby was dead weight so heavy enough to break the branch . </P> <P> Another possibility is that the words began as a "dandling" rhyme - one used while a baby is being swung about and sometimes tossed and caught . An early dandling rhyme is quoted in The Oxford Nursery Rhyme Book which has some similarity: </P> <Dl> <Dd> Catch him, crow! Carry him, kite! </Dd> <Dd> Take him away till the apples are ripe; </Dd> <Dd> When they are ripe and ready to fall, </Dd> <Dd> Here comes baby, apples and all, woop woop . </Dd> </Dl> <Dd> Catch him, crow! Carry him, kite! </Dd>

Where did the nursery rhyme rock a bye baby come from