Pro vs. Dative

Latin Learning Latin
1

Salve,
Many times it seems that the dative could be used in place of ‘pro’ since pro means ‘for.’ For example:

Dative -
Illa opem servis dedit. (That woman gave help to the slaves.)

Pro -
Illa opem pro servis dedit. (That woman gave help for the slaves.)

These sentencesa aren’t identical, but the idea is similar. Any comments?

Gratias ago.

Vale,
EL

2

The second sentence means that the woman gave help on behalf of the slaves. She wasn’t helping the slaves, but helping someone else whereas the slaves formerly should have been doing so.