'peacefully-developed' originates from the combination of 'peacefully' and 'developed', where 'peacefully' is derived from 'peace' and '-fully', and 'developed' is the past participle of 'develop'.

'peacefully' changed from the Old English word 'pēas' meaning 'peace' and '-fully' from the Old English '-ful', while 'developed' comes from the Old French 'desveloper', meaning 'unwrap'.

Initially, 'peacefully' meant 'in a state of peace', and 'developed' meant 'unwrapped or unfolded', but over time, they evolved into their current meanings of 'in a peaceful manner' and 'having been developed', respectively.