No resources.

[oldskald]

Cannons require iron though.

True, but I was assuming that the OP might want to do some conquering before the Industrial Era and rectify the lack of resources. Or perhaps I'm thinking too much about what I'd do...

 

[Ambidexter]

After you get gunpowder your infantry units don't require resources. You still need horses for cavalry and oil for tanks.

 

[r_rolo1]

After you get gunpowder your infantry units don't require resources. You still need horses for cavalry and oil for tanks.

Technically you don't need oil for tanks. Standart Ethanol does the job for tanks as well

 

[mizzile]

Yeah, there was once when I forgot that little detail and rushed to steel and it took me a sec to realize why I couldn't upgrade my trebs. DOH

1.
2. It's speeled P) "D'OH"