104 come in with lyre playing for declaration of love (5,8)

'declaration of love' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'104 come in with lyre playing' is the wordplay.
I cannot quite see how this works, but
'104' could be 'civ' (roman numerals) and 'civ' is located in the answer.
'playing' could be 'on' and 'on' is located in the answer.
This may be the basis of clue (or it may be nonsense).

'for' is the link.

Can you help me to learn more?