Proverbially rich man cross accepting EU split? (7)

I believe the answer is:

croesus

I'm a little stuck... Click here to teach me more about this clue!

'proverbially rich man' is the definition.
'croesus' can be an answer for 'man' (I have seen 'Rich man' mean 'croesus' so perhaps 'man' could also mean 'croesus'). I'm not certain of the 'proverbially rich' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for croesus that I've seen before include "wealthy ruler" , "One famously loaded" , "Rich old king" , "Very rich person" , "King of fabulous wealth" .)

I've seen this clue in The Sun.

Want a hint initially instead of a full solution? Install my app