The number of kings that Jesus toppled is exactly zero, unless one wants to argue that Jesus is responsible for the toppling of kings that was done in his name in subsequent centuries.  But this is clearly not what Brown means, since his point in this passage is to argue that there are lots of historical records besides the canonical New Testament texts, and his argument would be on point only if these records came from the same time period.  Brown’s estimation of the fame and popularity of Jesus during the time the New Testament was being written is sadly mistaken, however.  The fact is that despite the impression created in the gospels of thousands of people following Jesus, he was simply not a figure of staggering influence during his lifetime or for decades thereafter  Only one Jewish writer of the time (Josephus) even mentions him.  In the Greco-Roman world Jesus’ existence created nary a ripple.  As Bart Ehrman writes:

“How many times is Jesus mentioned among the hundreds of documents by pagan writers (i.e. those who were neither Jewish nor Christian) that survive from the first century of the Common Era—writings by historians, poets, philosophers, religious thinkers, public officials, and private persons, including literary texts, public inscriptions, private letters, and notes scribbled on scratch paper?  Not a single time.  There are no birth records, official correspondence, philosophical rebuttals, literary discussions, or personal reflections.  Nothing written by any pagan author of the first century so much as mentions Jesus’ name.  The first reference to Jesus in a pagan source comes some eighty years after his death, in a letter written in 112 C.E. by the Roman governor of Bithynia-Pontus, Pliny the Younger . . . “ (Bart Ehrman, The New Testament 212).

Brown’s depiction of a Jesus whose arrival on the scene created such a spectacular impact that “countless” people began “chronicling” his life and “thousands” of documents were created is so fundamentally wrong that it calls into question virtually anything else he might have to say on the matter.  The ignorance here is just staggering.