And Muhammad, as we talked about, was born roughly in 570 and dies in 632. And on this timeline here, the white period is before, according to Muslim traditions, that he started having the revelations from God. And the brown period is when he's having these revelations and he's starting to be the leader of this nascent Muslim community. Now what we see here in this dark brown is what was in control of this Muslim community at the time of Muhammad's death. And you see, even by that period, they had control of a good chunk of the Arabian Peninsula. And what's particularly surprising is how fast Islam spread shortly after that. The next period, after Muhammad dies, the leadership of the community, of the ummah, goes to the caliphs.