The senate was responsible for paying the salaries of soldiers in the Roman Republic.
The Roman soldiers were payed by the senate but they do not pay them from their pocket. The senate raised a new tax on the public to collect the fund for the soldiers pay. So, the senators paying salaries to the soldiers depends on the public taxes.
Judging from your other questions, I would guess the Aztecs, because they had an extremely advanced civilization relative to their time period. However, you might want a second opinion to verify this. Hope this helps.
