The Toa Mata were placed in canisters and shot into the sky long ago. They were ment to land on Mata nui but something went wrong. Instead they drifted in the sea for a thousand years. The pods did not beach on the island until Takua the chronicler collected all of the toa stones and placed them together at the temple of Kini nui. This somehow drew the pods to the island. The canisters beached at different locations. When the toa emerged they had no memory of their past lives. They met up after wandering around the island for a day or so, then they met the matoran and the turaga. They had awaited the Toa's arrival. the turaga were the wise leaders of the matoran villages. They new the toa names and purpose. There names were: Tahu, toa of fire, Gali, toa of water, Lewa, toa of air, Kopaka, toa of ice, Pohatu toa of stone, and Onua, toa of earth. They were meant to save the island from the Makuta. Tahu became the leader.
Quest for the Masks
The toas' first mission was to recover five each of the Great Kanohi masks, in addition to the ones they had, that would allow them to defeat the Makuta. They aquired the masks nad were able to combine them into golden masks that had all the powers of the six seperate ones. They descended the underground tunnels of the island and met the manas nui, the fierce guradian of the makuta. They were able to beat it by transforming into the toa kaita. Tahu, Pohatu, and Onua became one and Gali, Lewa and Kopaka became the other. They then faced shadow versions of themselves. They were able to defeat them and emerged form the tunnels, victorious for the time being.
The Bohrok Swarms
After they emerged from the tunnels, the toa fought the Bohrok swarms, creatures that wanted to cleanse their island of all buildings, trees, mountains, and rivers. The toa were forced to obtain one of each species of Krana from each of the Bohrok species.