I was watching a documentary last night about Venice, and it reminded me of how I've always felt that there's a bit of a "Venetian Gothic" thing going on with the Navis Nobilite. It struck me that 40k, with its determination to mine every martial archetype for its armed forces, can miss out on evocative and compelling archetypes from less militaristic cultures. 

Here's a few thoughts on historical archetypes which could inform aspects of the 40k setting:-

• The Navis Nobilite work well with the aforementioned "Venetian Gothic" look. I've always imagined them as a cosmopolitan, decadent lot. Sinophia actually trades on some of these archetypes (derelict ancient canals etc) but I always pictured it going further, with an orbital "City of the Navigators" at the heart of each Imperial Sector, where they politick and scheme against each other. 
•   The Navis Nobilite also work well with mafia and crime archetypes, as well as inbred bayou families and eccentric millionaire concepts.
• I'm a big fan of Byzantine history, and I think the cultural impact of that civilisation gets missed, both in the minds of most people and in 40k. There were encouraging signs in 5th ed that there was interest in a "split Imperium" concept, a bit like the breakup of the Roman Empire into an Eastern and Western side, but that's not really been explored any further as of yet. 
• er…
• That's all I've got time for at the moment, my internet access is time limited. I will drop in some more thoughts when I can! Anyone else got any thoughts? 

Well, Navigators are going to share an upcoming splat-book with Astropaths next year. I'd imagine it will go into greater detail on the local Houses in and around the Calixis Sector.

Lightbringer said:

However, I think it is meant to be more inspired by the Great Schism and the Avignon Papacy than the split of the Roman Empire…