How do I get Genghis Khan to invade Peking?

Hint 1 of 13:

You're going to have to open those gates yourself.

Hint 2 of 13:

Of course, you'll need to get inside the city first.

Hint 3 of 13:

That means you have to get the password to get inside.

Hint 4 of 13:

A certain merchant will tell you if he thinks you deserve in.

Hint 5 of 13:

Have you been to Baghdad, 1215 AD?

Hint 6 of 13:

If you sell him the right thing, he'll give you a password.
(See the question about the merchant in the Baghdad, 1215 AD, section.)

Hint 7 of 13:

The password happens to be TOWER GATE.