Anwar al-Aulaqi, a U.S.-born radical Islamic preacher who became one the most influential al-Qaeda operatives in Yemen, was killed Friday in an airstrike in northern Yemen, authorities said.

Anwar al-Aulaqi speaks in a video message posted on radical Web sites in November 2010. (AP)

His name became synonymous with fiery Internet sermons that called on Muslims to rise up in jihad. So many of those sermons ended up on YouTube that he was known by some as the “YouTube Islamist.” Below are several of those sermons, in which he preached on everything from abortion to the Byzantine Empire:

On abortion:

On obesity:

On why we hate death:

On what he saw as the qualities of a “true Muslim”:

On the Byzantine Empire:

On paradise vs. hell:

Aulaqi also recorded many videos centering on hatred of America. YouTube has disabled the embedding of those videos.