'strongly-held' originates from the combination of 'strongly' and 'held', where 'strongly' is an adverb form of 'strong', meaning 'with great force or intensity', and 'held' is the past participle of 'hold', meaning 'to keep or maintain'.

'strongly-held' evolved from the Middle English word 'holden', which meant 'to grasp or keep', and 'strong', which has been used since Old English to denote 'powerful or firm'.

Initially, it meant 'to keep with strength', but over time it evolved into its current meaning of 'firmly believed or maintained'.