The economic layer of Brotherhood's liberation — buying the shops, funding the guilds, restoring the aqueducts, rebuilding the infrastructure that Borgia control has allowed to decay. Steel is necessary and insufficient. The city has to believe in its own possible future, has to have the material conditions for daily life to function, before the liberation becomes something the citizens can sustain rather than something Ezio has to maintain indefinitely.

Faith and fire are the Assassin's two contributions: the belief that a different Rome is possible, and the specific heat that burns away the Borgia structures preventing it. The faith is political. The fire is the Brotherhood.