In the last years of the Republic, the Trade Federation turned to weapons makers ranging from the Geonosian hives to Baktoid Armor Workshop to create droid armies and assault vehicles. When the blockade of Naboo became a full-fledged invasion, droid-piloted AAT battle tanks rolled into the graceful city of Theed, overwhelming opposition.

When the Gungan army marched on Theed, the Trade Federation countered by sending AATs out in armored columns to meet the Gungans on Naboo’s plains. The Neimoidians were confident that the amphibians and their odd assortment of weapons were no threat.

The Gungans battled the tanks by catapulting the heavy plasma grenades they called boomas at the droid lines. But withering fire from the AATs broke the Gungan lines.

Jar Jar Binks, of course, managed to take out AATs through his unique brand of chaos. And the battle tanks were rendered useless when the Trade Federation’s Droid Control Ship exploded, causing the battle-droid pilots to shut down.

The Trade Federation’s invasion failed, but the AATs had proved impressive in battle. When the Clone Wars began, Baktoid factories produced countless battle tanks for the armies of the Separatists. On Christophsis, armored divisions smashed through the planet’s graceful crystal cities.

The Separatist ground attack on Christophsis was led by General Whorm Loathsom, commanding his armored columns from the turret of his personal AAT.

The fight on Christophsis was primarily a duel between the Republic’s powerful AV-7 cannons and Loathsom’s AATs, with control of the strategically located Outer Rim world in the balance.

Loathsom had an advantage, however – his AAT columns were defended not only by octuptarra droids but also by a mobile shield generator whose protective energy field was impervious to fire from the AV-7s.

Loathsom moved his forces steadily towards the AV-7s, pushing the Republic’s clones back. Anakin Skywalker and his new Padawan Ahsoka Tano hid themselves on the battlefield, letting the shield perimeter pass over them as the AATs passed.

While Anakin and Ahsoka fought their way to the shield generator, Obi-Wan Kenobi stalled for time, surrendering to Loathsom and then drawing out negotiations while sitting in the shadow of the Separatist general’s AAT.

Anakin and Ahsoka brought down the shield, and the AV-7s battered the AATs. When Republic warships punched through the Separatist blockade of Christophsis, the battle turned decisively in the Republic’s favor.

On the coral moon of Rugosa, Yoda made a bet with Asajj Ventress to determine the allegiance of Toydaria’s King Katuunko – Yoda and his small band of clones would take on Asajj’s droid army, complete with AATs, to demonstrate which side had the best chance of defending Toydaria in the Clone Wars.

Ventress had the military might, but the clones had Yoda, who led the droid army on a merry chase, then ignited his lightsaber and made short work of the AATs.

On Maridun, the Separatist weapons researcher Lok Durd brought AATs to subdue the planet’s population of pacifist Lurmen. Durd then tested a modified AAT, the Defoliator Tank, on the planet’s vegetation.

Anakin, Ahsoka, and Aayla Secura joined a small force of clones and Lurmen to defeat Durd’s droids, with Anakin destroying the Defoliator Tank and capturing the Separatist researcher.

On Ryloth, the tactical droid TX-20 defended a key artillery position by using Twi’lek prisoners as living shields, preventing Republic bombardment. But TX-20’s gambit failed when the Twi’leks rose up, swarming his AAT and tearing him mechanical limb from limb.

The Republic advance on Ryloth’s capital city of Lessu was a grueling one, as AATs rained fire on Republic AT-TEs advancing along a winding cliffside road. Mace Windu and clone scouts destroyed the AATs using mobile AT-RTs.

On Geonosis, Republic forces landed under heavy fire, winding up short of their designated landing zone. Geonosian drones and Separatist droids then launched a deadly counterattack using AATs.

After the collapse of the Separatist defenses on Geonosis, Archduke Poggle the Lesser fled to the Progate Temple in an AAT pressed into service as a transport.

On Malastare, the Republic’s experimental electro-proton bomb proved a highly effective weapon, shutting down a Separatist droid army with an electromagnetic pulse that left deactivated AATs sitting still on a silent battlefield.

On Naboo, General Grievous’s attempted alliance with the Gungans came to naught when Minister Rish Loo’s treachery was revealed and Grievous' AATs and battle droids were shut down, leading to the cyborg general’s capture by the Gungans.

Grievous survived that reversal, and led Dooku’s invasion of Dathomir. His AATs advanced through the planet’s gloom, massacring Mother Talzin’s Nightsisters.

AATs were once again in the vanguard as the Separatists occupied Onderon, supporting the puppet king Sanjay Rash.

The Jedi Council sent Jedi and clones to train Onderon’s rebels in insurgent tactics, such as how to disable an AAT with electromagnetic pulse grenades.

The Onderon rebels soon had to test their mastery of these new tactics, as King Rash’s droid forces attacked their jungle camp with AATs.

Steela Gerrera’s rebels infiltrated Onderon’s capital of Iziz, where they deactivated and captured an AAT after a pitched fight with a battle-droid patrol.

Steela rebooted the tank’s systems and the rebels used its heavy cannon to destroy Iziz’s power generator, leaving the capital in darkness.

King Rash’s forces counterattacked, chasing the rebels into the jungles. Steela’s rebels were able to handle the columns of AATs, but fell back when attacked by droid gunships.

On Florrum, Hondo Ohnaka paid the price for having captured Count Dooku when General Grievous overran his pirate base with AATs.