The name 504 refers to the total number of game mechanic combinations that can be formed using the nine game “modules” included in the box: Pick-up & Deliver, Race, Privileges, Military, Exploring, Roads, Majorities, Production, and Shares. Essentially, 504 is a "game toolbox" that players use to create a variety of different game experiences, united by common elements.
504 is being co-published with German game publisher 2F-Spiele. MSRP has not yet been set. The game is scheduled to debut at the Spiel fair in Essen Germany this October, with general release to follow in November.
Stronghold’s first "Great Designer" game was Kramer and Kiesling’s Porta Nigra (see "'Porta Nigra' From Award-Winning Design Team").