Oops, Birbin's 'why?'. Consider it corrected. Sorry about that, saw your familiar sword and accidentally conflated it.
That said, sure, I'm sure it worked back then. New edition seems pretty adamant about general magic resistance being fairly unbalancing.
If the Parma is a spell it causes warping.
Aegis: interesting reason.
That "why" was mine. I like to know why a change was made.
People recognize me by the flaming sword, awesome!
All that is left is to legally change my name to Reculed Seneca 
Only if you use it all the time... 
Now, if you wanted a House Rule I really didn't like, you'd have to go with 'Arts advance as Abilities.' No offense to whoever did that. ;D
Now there's something I'd see and go 'Yeah, I think I'd rather be a Hedge Wizard or even a mundane.'
House rules for my campaign? Not many. As I Storyguide, I like to keep my job as streamlined as possible, so I just use the number 6 whenever there's an opposed roll between an NPC and a PC. So in effect, combat becomes less random, and based on the players trying to beat Ease Factors instead of opposed rolls. They really like this, and it speeds things up a lot. And if the NPC is wounded, the player gets the wound penalty as a bonus instead.
Also, I'm gradually introducing an expanded combat system I'm working on into my campaign. Just need to chip away more rough edges, then it should both speed things, give more options for the creative combatants and give it more realism (from our point of view). 
Oh, and we let players decide if they want to spend Confidence after the roll is made.
E.
" we let players decide if they want to spend Confidence after the roll is made"
isn't it RAW?
Is it? I'm not sure, actually. Anyway, we do it
E.
Our troupe has an unwritten houserule that everybody brings something to drink and something to eat, and that we all share. 
That's the best houserule I ever heard.
Doubly so if everyone follows it, since it's an unwritten one. 
In mgroup those that don't bring something to eat/drink have a weird tendency to be the target of most accidents and misunderstandings. Weird how that happens 
heheh
Cheers,
Xavi
I was SG'ing a saga set in Constantinople, city of a million.
I was working in a market, and tried to always bring a bottle of Retsina and a peasant loaf of olive bread along with a bottle of olive oil for dipping. Yummy and mood setting.
House rules may have three uses from my viewpoint:
-When a game is out hundreeds of people will play it and many mistakes appear what the few testers weren't able to find. These rule changes correct the errors.
-The second group brings some little changes reflecting different tastes.
-And the rules which change the game a lot. Like this:
In my gaming group we use the 3 kind of changes listed above. As usual, it is a "whatever makes you have more fun" proposition here
Cheers,
Xavi
It really doesn't. As far as I can see - havn't tested it extensively yet.
I'm currently starting a companion-focused game, and using the above (I figure it would discoruage creating magi). So this can be a taste-oriented house rule as well.
It brings up the question of why Bonisagus bothered. Considering an 80 year old wizard would be lucky to have art scores of 5 across the board... (that's 1125 experience versus 225 experience.) I s'pose if they found level 5 quality books for each one it would be a bit easier to approach, but still...
Ah well, it works for the game, aye?
You'd need to seriously cripple Hedge Traditions, though, wouldn't you? Even with the Parma Magica, it's hard to see how such an anemic Order could have spread.
As for Companion oriented... Ever since I picked up my delicious Art and Academe, I've been thinking of running a Bologne game. (Possibly OoH is nonexistant so hedge traditions are more important.) So I can certainly sympathize. ;D
Something of the players in my saga sent to me...
Art scores are halved. Parma value is extremely high, I suppose you would lower it. Supernatural beings are more powerful, teaching apprentices is quite hard, spontaneous magic is useful only to the elders. Healing and creating towers is only for specialists. Pilum of Fire is the most powerful spell for the freshly gauntleted Flambeau. Hedge magi must be even weaker or they may be more powerful than the hermetic magi. Thus it provides more story potential.
I think it is more than a little flavor it's a low magic campaign. Anyway I wouldn't say it is inferior to the usual game but different. It resembles me to the D&D where the sleep was the young wizards' most important attacking spell. This is roughly the same power level at the beginning. And unlike to both of the original games the magi will be less powerful in their old ages.
I would like to play such a game. Far better than the fantasy magic system.
If the real magic traditions (divinations, alchemists, gnosticism, philosophers' stone etc.) are published in the new supplements it would be easier to run such a great campaign. This would be also a low magic campaign but a bit more mystical.
Hmmmm, no Order... The magic of the founders... We can rebuild it (as hedge traditions)! We have the technolgy!
I suppose everybody has thought about that in some moment of his life as an Ars Magica player or SG (or both).
Xavi