Building of a mosque at site of a victory?

Please help me with something.  In discussing the ground zero mosque last night with my son, he asked me to find authority for the proposition that the mosque was being built as a part of a Muslim tradition of building mosques at the site of their victories.  As the most knowledgeable group of people I know (yeah, that’s sucking up, but it’s also true!), I’m asking for your help.

What authority do you know of, authority that would persuade an open-minded but skeptical fellow like my son, that Muslims generally have a tradition of building mosques at the spot of their victories and/or that this particular mosque was proposed as a part of that tradition?  What else do you know about that whole dispute that might be useful in my discussion with my son?

Thanks, DQ