OED: Mahdi (see the word, impostor...)

[grladams at mail.teleport.com]

  Hence Mahdiship, the dignity or position of a Mahdi; Mahdism,
 Mahdi-ism, the rebel movements in the Sudan about 1880-1885, and
subsequently, under leaders claiming to be the Mahdi; Mahdian, Mahdist,
 Mahdi-ist, an adherent of a pretended Mahdi.
 
  1884 19th Cent. May 816 The impostor who has..laid claim to the Mahdiship.
1884 Times
(weekly ed.) 29 Aug. 1 Mâhdism is essentially a Shiya doctrine. 1885 Pall Mall
G. 10 June 3/1
Mahdi-ism is in his eyes a real danger. 1885 Daily Tel. 19 Feb. 5/2 A
demonstration..was..made against Metemneh, in order to draw the Mahdists off.
1885 Ibid. 21
Mar. 5/1 No hardy Mahdian got nearer than twenty yards. 1891 Daily News 18 Dec.
6/1 The
invasion of Egypt by the Mahdiists in August, 1889. 1897 Ibid. 22 Sept. 6/4
Gordon, and Sir
Samuel Baker..were even more responsible for the rise of Soudanese Mahdism than
the Mahdi
himself.
 

-from the OED. 

I like the particularly interesting aspect that one of England's own, and one
with varying levels of respect and admiration, would be responsible for its
uprising. These and other dualities and flip flops are what are interesting
about this time period in history. I have been reading the Mahdist state in the
Sudan / P.M. Holt 2nd ed 1970.
What strikes me particularly about this period in history there in Egypt is how
confusing it is, how hard communication was. Instructions from Britain were
misunderstood by Gordon, and relayed to the Egyptians and Sudanese leaders with
particularly poor tact. Gordon's goals were not clear and he seemed to make flip
flops in decision making.
He seems particularly tragic, as if the ones still in Britain leave him to
squirm in a difficult situation. By the way, Gordon was considered a pederast
and a drinker. The parallels with the action in V are that there is some
changeability, some codes being broken, flip flopping going on, the idea of
impostors around, or people whose sympathies are 
changeable.

-jill