To conquer Colonies 20 and 21 in Grow Empire: Rome without stalling your city defenses, alternate between clearing defense waves and launching offensive campaign sieges. Clear Waves 51 and 52 to gather baseline gold, capture Colony 20 using staggered melee waves, defend Waves 53 and 54 while collecting passive colony tax, and then breach Colony 21 before completing Wave 55.
Coordinating Progression Between Waves and Sieges
Pushing past Wave 50 increases enemy pressure at your gate. Enemy waves from 51 through 55 introduce denser infantry lines and aggressive raiders that deal rapid damage to your wall if melee combat stalls. Relying strictly on wave income creates a gold bottleneck because upgrade costs for walls and towers scale rapidly. Capturing Colonies 20 and 21 establishes passive tribute that offsets these rising costs.
Follow this progression sequence to balance income and defensive power:
- Clear Waves 51 and 52: Farm initial gold from incoming waves to level your barracks infantry before launching your first campaign march.
- Besiege Colony 20: March on Colony 20 and defeat the garrison to activate its automated tax collection immediately.
- Defend Waves 53 and 54: Let passive income accumulate alongside wave rewards to fund upgrades for your wall archers and wall durability.
- Besiege Colony 21: Attack Colony 21 with reinforced units to secure the second passive gold stream.
- Clear Wave 55: Finish Wave 55 with your upgraded wall defenses and reinvest the surplus gold into your core army.
Recommended Army and Wall Setup
Surviving Waves 51 through 55 and cracking enemy colony garrisons relies on a balanced core of wall-mounted archers, swordsmen, and spearmen.
| Unit or Structure | Primary Role | Defensive Role (Waves 51–55) | Offensive Role (Colonies 20–21) |
|---|---|---|---|
| Roman Archers | Sustained Ranged DPS | Kills light raiders and thins enemy infantry before they reach the gate | Defends the city walls while cohorts march on the map |
| Roman Swordsmen | Frontline Melee Anchor | Blocks enemy clusters directly in front of the wall | Absorbs tower arrow fire and breaches defensive palisades |
| Roman Spearmen | Anti-Cavalry Melee | Stops fast cavalry charges before they strike the gate | Counters mounted garrison defenders behind the gate |
| City Wall & Towers | Structural Defense | Prevents wave breaches with high hit points and automated catapults | Serves as the primary defensive anchor between campaign sieges |
Tactical Execution for Colonies 20 and 21
Colonies 20 and 21 feature fortified gates backed by elevated archers and responding garrison units. Rushing your entire army across open ground at once exposes them to concentrated tower volleys, which can wipe out your cohorts before they reach the barricade.
Use a two-wave assault pattern to breach both settlements:
- Deploy the Vanguard: Send an initial cohort of Roman Swordsmen across the field. Their armor absorbs the opening arrow volleys from the watchtowers and draws out the first wave of garrison defenders.
- Deploy the Main Force: Once the garrison engages your swordsmen, immediately send a mixed reinforcement wave of Swordsmen and Spearmen. Spearmen quickly eliminate defending cavalry, while fresh swordsmen attack the gate.
- Trigger Abilities at the Barricade: Activate commander offensive buffs as your second wave arrives. Fire boulder strikes or siege skills directly at the barricade when defenders cluster tightly behind it.
Surviving Damage Spikes in Waves 51 to 55
Enemy compositions in Waves 51 through 55 feature coordinated shock infantry pushes designed to overwhelm your gate quickly.
Do not activate abilities like the general's War Horn or offensive strikes on the early scout units that appear at the edge of the screen. Premature activation wastes ability uptime, leaving you vulnerable on long cooldowns when the main horde arrives.
Allow your rampart archers to shoot down advance runners on their own. Wait until the bulk of the enemy infantry halts directly against your wall or engages your deployed melee units. Activating damage buffs and catapult strikes at that exact point of contact maximizes area-of-effect damage, clearing the cluster quickly and preserving wall health.
Gold Reinvestment Priorities
Once Colony 21 is secured, allocate your incoming tax revenue and wave rewards across three key upgrades:
- Roman Archer Count and Damage: Invest the majority of your funds into rampart archers. High ranged damage per second eliminates the vast majority of standard wave attackers before they reach your gate.
- Wall Hit Points: Upgrade baseline wall durability to absorb delayed ability timing or sudden burst damage during Waves 54 and 55.
- Barracks Unit Levels: Level your Roman Swordsmen and Spearmen to ensure your mobile army maintains the stats required for higher-tier colony sieges beyond settlement 21.
Free Grow Empire: Rome Codes
Current active codes and how to redeem them.
Emily Johnson
Emily writes practical mobile strategy guides with a focus on resource planning, base progression, and the early decisions that shape a long-term account.
COMMUNITY
Player Comments
119 players commented on this guide.
This helped me understand strategy much better.
I tried this today and it worked better than my old setup.
I wish I had read this before upgrading the wrong thing.
Nice guide. I am checking the other Grow Empire: Rome articles next.