In particular, there are three strong guest stars - Julian Glover as Richard the Lionheart, Jean Marsh (ex-wife of future Doctor Who Jon Pertwee) as his sister Joanna, and Walter Randall as the fictional villain el-Akir (Randall's career seems to have been otherwise not awfully memorable bit parts but he did this pretty well, I thought). I'll put in a word also for Viviane Sorrell as Fatima, who (according to IMDB) never played another role on-screen. And the regular cast are good (though Vicki not given much to do).
The plot is a fairly basic "time-travellers get caught up in real historical events and spent most of the story untangling themselves" one but done effectively, with a real sense of different places as between Crusader-controlled Jaffa and Saracen-controlled Lydda. (Though the thicket in which the Tardis lands does not look in the least Palestinian.) Of course, because the Doctor and Barbara know their history, this gives rise to the usual potential for time paradoxes, though with a certain air of wistfulness:
VICKI: Doctor, will he really see Jerusalem?A particularly striking aspect is the use of rhythm in the script. I found one website claiming that parts of it were actually written in iambic pentamenter, and, well, it's nearly true; see what you think.
THE DOCTOR: Only from afar. He won't be able to capture it. Even now his armies are marching on a campaign that he can never win.
VICKI: That's terrible.
THE DOCTOR: Hmm!
VICKI: Can't we tell him?
THE DOCTOR: I'm afraid not, my dear. No. History must take its course.
RICHARD: We think our words were plain enough.Perhaps I should start writing my livejournal entries in blank verse. I know of two people who do all theirs in haiku - which is all very well, but I tend to have more to say.
THE DOCTOR: It is
a good scheme, sire, if the princess agrees.
RICHARD: (quietly) Joanna knows nothing of this matter.
THE DOCTOR: Will she agree?
RICHARD: (firmly) You should rather ask
how can she refuse? To stem the blood,
bind up the wounds and give a host of men
lives and futures? Oh, now there's a marriage
contract to put sacrifice to shame
and make a saint of any woman.
with all the strength at my command I urge you,
sire, to abandon this pretence of peace!
THE DOCTOR: (angrily) Pretence, sir? Here's the opportunity
to save the lives of many men and you
do nought but turn it down! Without any
kind of thought. What do you think you are doing?
LEICESTER: I speak as a soldier. Why are we here
in this foreign land if not to fight?
The Devil's horde, Saracen and Turk,
possess Jerusalem and we will not
wrest it from them with harried words.
THE DOCTOR: With swords, I suppose?
LEICESTER: Aye, with swords and lances, or the axe.
THE DOCTOR: You stupid butcher! Can you think
of nothing else but killing, hmm?
LEICESTER: You're a man for talk, I can see that.
You like a table and a ring of men.
A parley here, arrangements there, but when
you men of eloquence have stunned each other
with your words, we, we the soldiers
have to face it out. On some half-started
morning while you speakers lie abed,
armies settle everything, giving sweat
sinewed bodies ironed life itself.
THE DOCTOR: I admire bravery and loyalty, sir.
You have both of these. But, unfortunately you haven't any brain at all. I hate fools!
LEICESTER: A fool can match a coward any day.
(Leicester pulls out his sword and faces the Doctor.)
RICHARD: Enough of this! (to Leicester)
You dare to flourish arms before your King?
(Leicester reluctantly sheaths his sword.)