Okay there is something weird going on. I'm not sure if this is the API or a inconsistency in the database. I want to get the first revision (and optionally n revisions after that). This does work with the `The Big Bang Theory` article [[http://en.wikipedia.org/w/api.php?action=query&prop=revisions&rvprop=ids%7Ctimestamp&rvlimit=1&rvdir=newer&titles=The%20Big%20Bang%20Theory&rvendid=145491640|`titles=The Big Bang Theory&rvendid=145491640`]]. The `rvendid` is not the ID of the first revision but some revision I choose randomly. It does return me the first revision visible by the parentid.
Now this is a different story on the `Main Page` [[http://en.wikipedia.org/w/api.php?action=query&prop=revisions&rvprop=ids%7Ctimestamp&rvlimit=1&rvdir=newer&titles=Main%20Page&rvendid=139871|`titles=Main Page&rvendid=139871`]]. It now returns directly that revision which might be because it's parentid is higher than it's current id. Even [[http://en.wikipedia.org/w/api.php?action=query&prop=revisions&rvprop=ids%7Ctimestamp&titles=Main%20Page&rvstartid=139890&rvdir=older&rvlimit=50]] this is just returning two revisions.