'richly-made' is a Modern English compound formed from 'richly' + 'made'. 'richly' derives from 'rich' (Old English 'rice' / Old High German 'rihhi'), where the root meant 'powerful' or 'wealthy'; 'made' is the past participle of 'make' (Old English 'macian').

'rich' developed from Old English 'rice' (meaning powerful, wealthy) and entered Middle English as 'rich'; the adverbial form 'richly' was formed by adding the -ly suffix in Middle English. 'Make' comes from Old English 'macian' and became 'make' in Modern English, with 'made' as its past/past-participle. The compound 'richly-made' formed in Modern English by combining the adverbial modifier with the past participle to describe the manner of making.

Initially the components referred separately to wealth/power ('rich') and the action/result of making ('made'), but combined they came to mean 'made in a wealthy or lavish manner' and, by extension, 'elaborately or high-quality constructed'.