[quote]Can someone explain to me the difference between the greater and lesser arks? When I red the wiki it seemed really diluted and non-concrete info.[/quote] Greater Ark was constructed first, it created the original twelve 30,000km diameter Halos. The Lesser Ark was created in secret, and was used to create the 10,000km diameter Halos which were used to cleanse the galaxy. [quote]I.e: Which one is installation 00? What was the battle between gamma halo and the greater ark? We're there "larger" halo rings? What's the difference between the two? Is the lesser ark 00?[/quote] The Lesser Ark is Installation 00. The Greater Ark was called the Beginning Place. The battle of the Greater Ark really wasn't a battle at all, it was over in mere moments. While the Lifeworkers were going about cataloguing and indexing species on the Lesser Ark, the majority of the other surviving Forerunners rallied at the Greater Ark with the Master Builder, IsoDidact, Bitterness of the Vanquished, and other military and strategic leaders. They were to fire Omega Halo at the LMC to slow the Star Roads' approach into the Milky Way. They succeeded in firing the Halo and slowing the Star Roads, while cutting about a million ships out of Mendicant Bias' fleet for the final confrontation at the Maginot Sphere. However, the Star Roads smashed Omega Halo and the Greater Ark apart in seconds. As far as we know, only the IsoDidact managed to escape with the help of Chakas where he then went to the Lesser Ark to fire the other Halos. [quote]Also: how close is Requiem to the Ark? I'd imagine it would be pretty close but I wouldn't be too surprised if it wasn't considering Forward unto Dawn was drifting through space for quite a while.[/quote] Nowhere near. Requiem is in the Milky Way, in the Epoloch system. Mendicant Bias rerouted the portal at the end of Halo 3 to send John to Requiem.