Sixteen Thirty Something is a design by Martin Wallace (who also designed Steam) dating to 1995. This version is a redesign by Danny Stevens, and has been released as a free "print and play" game with Wallace's permission.
Although the game has something of the color of the period, it is not, as you might expect, a Thirty Years' War game. Instead, it's a strategy game in which players, theoretically representing large merchant houses, have influence in the various countries which they use to attempt to earn victory points. Wars occur, but are highly abstracted.
At the start of the game, each player receives a number of secret "victory point markers" printed with the names of different countries. At the end of each turn, a player earns victory points for each of these countries, if he has influence there, with the point award being the smaller of the country's current "status" (a measure of prestige and power) and the player's influence in the country. There are multiple markers for each country, so that, say, two players could both be earning for Denmark, or one player earning doubly there. Players calculate their own VP totals, with only the totals revealed each turn, so it may be possible to infer, as the game goes on, what powers each player has VP with, but it is never overtly revealed, at least until game end. This, coupled with card hands, is the main source of uncertainty in the game.
"Influence" is in the form of cards, which players place in front of themselves, with a set of rules governing when new cards can be played, drawn, and so on. The main player conflict is in the form of "lobbying the crown," whereby a player attempts to get a nation to initiate a war with another nation; players vote their influence, with players able to play new influence cards in the process. The victor of a war gains status (and thereby may confer more victory points to players with that country's marker), and the loser loses military power.
The original version of the game had two main flaws; first, random allocation of cards and VP markers made it perhaps too luck-dependent, and second, there's an obvious positive feedback loop in terms of power status that tends to mean that, by midgame, some players are clearly in the lead and others pretty much out of the game, which is not a desirable effect.
Stevens's version redresses the problems and produces a considerably tighter can, at the cost of some additional complexity. Hand limits tighten over time, which makes for tenser play, and a system whereby a player's influence can be in decline (and the player unable to increase it) is added; this provides a negative feedback loop that redresses the positive one. In addition, a system is added to reallocate some cards among players each turn, which helps with the randomness issues.
On the whole, it's quite a good game with some novel mechanics, and worth the effort to assemble a copy to play. Stevens's version is, unfortunately, not particularly attractive from a graphic design perspective, though a fan contributed alternative game board helps. (It's designed for v1, though -- you'll still need the tracks from Stevens's game board).