Rome: Total War Cheats and Console Commands List has made a list of all the  Rome Total War console commands that are also know as cheats.

You can simply execute the  command function during the game by pressing the (‘) key, right above the tab, to make “RomeShell” down the cheat menu. Type in the code and also note that the system is really choosy about typos, so make sure that everything is right.

Other than that you need to press the tilde ~ key and enter these codes to use them. All codes are case sensitive so you must ensure to capitalize family member names, settlement names and everything else that needs capitalizing or it may not work.   

Console Commands
Code Effect
give_ancillary "character name" "catamite" [Subterfuge] gives a spy or assassin this ancillary= +1 subterfuge
give_ancillary "character name" "courtesan" [Subterfuge] gives a spy or assassin this ancillary= +1 subterfuge
give_trait "character name" "GoodDiplomat" 1-5 [Influence] gives any character between 1-5 influence- may or may not work on generals
give_trait "character name" "GoodSpy" 1-5 [Assassins] gives any character between 1-5 subterfuge- works on assassins too
give_trait "character name" "GoodAssassin" 1-5 gives any character between 1-5 subterfuge- works on spies too
create_unit "general's name" "unit name" "#" Add units to selected general. Example "create_unit "Gaius Julius" "roman velite" 2 "
adjust_sea_bed [value] Adjusts sea bed to specified height
add_population [settlement name] [amount] Allows you to give a city more population automatically. Max amount is 4000.
give_trait [character] [trait] [level number] Allows you to give any trait your faction can have to a specific general.
process_cq [settlement name] Anything in the city's building queue will be built automatically.
filter_coastlines Applys filter to world map coastlines
capture_settlement [city name] Captures indicated city
season [summer/winter] Changes season
date [year] Changes year
clear_messages Clears all stacked messages
process_cq [cityName] Completes the construction instantly of any town/city
oliphaunt Create a unit of Yubtseb Elephants
create_building [city] [building name] Creates a building in the named city.
diplomacy_mission Creates diplomacy mission
create_unit [Settlement/Unit] [unit name] [Amount] [experience] [defences] [attack] creates unit in a place or unit instantly with experiences/defence/attack if put
[command] Display help for listed command
show_terrain_lines Displays defensive terrain features
Jericho Enemy's walls collapse.
reset_display Forces display reset cycle
force_battle_defeat Forces local player's alliance to lose the battle
force_battle_victory Forces local player's alliance to win the battle
force_diplomacy [accept/decline/off] Forces opponent to accept diplomatic proposal
give_trait [General/FamilyMember] [Trait] [Level] gives a general/family member a trait instantly
mp [value] Gives character movement points
give_trait_points Gives character trait points
give_ancillary [character] [ancillary] Gives indicated character the indicated ancillary
add_money [amount] Gives you the specific amount of denarii you want. Max amount of 40000.
kill_character [character] Kills specified character
list_characters Lists all character in the world
list_traits Lists all traits
list_units Lists all units in an army
list_ancillaries Lists available ancillaries
invulnerable_general [general's name] Make the general invulnerable, may only work on battlefield
move_character [name] [x,y] Moves indicated character to specified coordinates
regenerate_radar Regenerates radar
reload_textures Reloads all textures
reload_shaders Reloads all vertex shaders
kill_faction [value] Removes faction from the game
character_reset Resets character to settings at start of turn
run_ai Restarts an AI turn sequence
amdb_max [value] Sets aerial map overlay depth bias for maximum zoom
amdb_min [value] Sets aerial map overlay depth bias for minimum zoom
amdb_offset [value] Sets aerial map overlay offset towards camera
diplomatic_stance [value] Sets diplomatic stance between two factions
set_building_health [value] Sets health of building of specifed type in a settlement
ai_turn_speed [value] Sets max speed of turn processing during AI round
show_battle_paths Shows all valid processed paths in pathfinder
show_cursorstat Shows cursor position and region ID
show_landings Shows landing positions available to AI from a given region
show_battle_street_plan Shows street plan for the settlement
victory Shows victory message for faction for short or long campaign
control [value] Switches player control to specified faction
building_debug Toggles building's debug mode
toggle_restrictcam Toggles camera restrictions
toggle_flowing_water Toggles display of campaign map flowing water
nw_stats Toggles display of network stats
toggle_perfect_spy Toggles everyone's spying ability to perfect with infinite range
toggle_fow Toggles on or off the fog of war. You can see the whole world map when inputted.
toggle_overlay Toggles overlay
toggle_pr Toggles PR mode
toggle_coastlines Toggles strategy map coastline display
display toggle_tow Toggles tabbed output window
toggle_terrain Toggles terrain to display various data sets
toggle_underlay Toggles underlay
trigger_advice Triggers advice
upgrade_effect Triggers unit upgrade effect
disable_ai Turns off both enemy and ally AI
auto_win [attacker/defender] When at the battle scroll, input this code in, attacker if attacking, defender if defending and press auto retaliate button. Automatically wins.
zoom [value] Zooms to specified aerial map zoom
add_money [20000] Adds money to your current funds.
add_money [40000] Adds money to your current funds.
bestbuy or gamestop Units are 10% cheaper.
auto_win attacker Attacker automatically wins the next auto resolved battle.
auto_win defender Defender automatically wins the next auto resolved battle.
burn_piggies_burn Set all Piggy Wings on fire.
list_units Lists all units in your army.
diplomacy_mission Creates a Diplomacy Mission.
diplomatic_stance Set the stance of the two factions.
force_diplomacy accept/decline/off Forces opponent to accept diplomatic proposal.
invulnerable_general charactername General is invulnerable in combat
disable_ai Allows you to roam the map without being attacked.
run_ai Re-enables the AI.
ai_turn_speed [number] Set AI turn speed.
list_traits Lists all traits
give_trait [character] [trait] [level] Gives the character the trait at the chosen level.
character_reset Resets character to default.
add_population [Settlement] [Number] Adds population to a current settlement.
process_cq [name of settlement] All building in settlement is completed, this only works on one settlement at a time.
create_unit [settlement] [unit_ID] [experience] [defenses] [attack] Creates a unit in the selected settlement or characters army with the stats you input
capture_settlement Captures the currently entered city.
create_building [city] [building] Creates a new building.
toggle_fow Toggles Fog of War.
jericho Walls will crumble.
oliphaunt Makes elephants 40%. This has been known to cause crashes, so use wisely.
date [year] Changes the years.
season [summer/winter] changes season.
move_character [character name] [X,Y] Moves character to location. Both X and Y need to be filled in with coordinates.