Reading through the Contested Isle, there does not seem to be a Mercere Portal in the entire tribunal. I find this an interesting opportunity for a story. Who would be interested in establishing a Mercere Portal in Hibernia and why? and where? Who would be invested in preventing the building of the portal? Would it need approval in tribunal (we know that the Hibernian peripheral code has many oddities) or could a willing Mercere magi just construct one. What do you think the story possibilities for any of the above circumstances could be?
Thanks in advance!
House Mercere tends to not build portals in areas that are considered "Dangerous". They also avoid building them in areas where they can not control access to them, to prevent others from learning the secret of building one. So part of the process of getting them to build a portal would be to convince the House that the area is both safe and under their control.
Even if the Tribunal wants one, you have the story of convincing House Mercere that the area is both safe enough and controlled enough. You would also have to convince them that the amount of traffic would be worth the extreme outlay of resources required to build and install one. Doesn't Hibernia have almost no Hermetic presence? That would make the convincing even more difficult.
So you have lots of story opportunities.
For the size of Hibernia it seems to have quite a lot of Hermetics. There are 11 defined covenants (including two Mercere houses that dislike each other) in Contested Isles and 1 in Through the Aegis. It does seem to be a Tribunal with a lot of turnover of covenants, the conflict between the Mercere Houses would be an issue, and it's generally viewed as the "wild west." There is also a canon one in Coventry (to Harco) and a Portal from Fudarus in Brittany to Durenmar. There are plenty of obstacles, particularly "what's the point when there are two pretty close by ship?" and "Which Mercere House gets the portal and how could you put it at one without upsetting the other?"
A side note is the Mercere in Hibernia have probably the easiest travel within the tribunal of any tribunal due to the Faerie High roads they use and the relatively small size.
It is possible that there is a faerie road which leads outside of Hibernia as well, likely stonehenge, Loch Leglean or Normandy.
The Giant's Causeway must go somewhere...
Sorry I was off by so much. I haven't played a game in Hibernia or spent a great deal of time reading the book. I could have sworn that there was little Hermetic presence there but most likely that is from an older edition of AM.
It is right that there is no Mercere Portal across Hibernia, but I do not think canon tells us whether or not there is a Portal out of the tribunal.
There are two reasons for not having internal portals. Firstly, there are the faerie high roads which the redcaps already use for speedy travel, and secondly, the island is small. There would be little to gain.
In our saga I have ruled that there is no Portal out of the tribunal. As @dc444 said, the redcaps can go to Fudarus or Coventry to use the portals there when they need to link to the rest of the Order. This breaks 3ed canon though, where Harco is said to have portals to every tribunal.
So who would be interested in erecting a portal? In my experience, the PCs always want another portal, and nobody else. PCs generally push towards modern infrastructure at every turn, so that every possible resource and convenience is available at there fingertips. This is not compatible with the medieval feel of the setting though, especially not with Hibernia which is insular, metaphorically as well as literally. A Hibernian magus promoting a portal would stick out like a sore thumb ...
It sounds like the native Irish magi would tend to be against the construction of a Mercere Portal. What could be reasons for the continental magi to support one? The more strange the better! A small coterie of magi pushing for the building of a Portal (especially if they are not Mercere) could be a good source for all kinds of conspiracies.
There doesn't need to be anyone against having a Mercere portal. There can even be many who would like to have one.
So why isn't there one there already if this is the case?
The obvious, and slightly boring, answer is that nobody is willing to pay for the portal. A Mercere portal costs a lot of vis to create. There can't be more than 3 or 4 mages in the entire Order who knows how to create one, and you need two of them to setup a Merecere portal. Those mages will have lots of demand on their time and require hefty payment for their services.
Then of course there is the little question of where the portal is to be located. Could be several covenants willing to pay at least part of the vis needed, but only if the portal is set up near their covenant.
The second question is where the other end of the portal should be. Most obvious choice would be Harcor, the Domus Magnae of House Mercere and one of the hubs for the Mercere Portal network.
Not everyone might like that choice though.
If I read you correctly, you are fishing for plot hooks, to make a saga revolving around an emerging portal project ...
One possibility is the faction who oppose the peculiarities of the Hibernian Peripheral Code, and who would like to see Hibernia better integrated with other tribunals, and maybe remerge her with Stonehenge. This intrigue has been ongoing for the better part of a century, but most magi who have been sent to investigate appear to blend into Hibernian customs, such as Lugardis of Elk's Run. Establishing a portal could enable a mission which remains part of a continental or English community. It may be a little too old-school Tremerian for some troupes, but certainly a playable plot for those interested. Funding should not be an issue, if the Tremere and the Quaesitores take interest.
A second obvious option would be a clique of very scholarly magi, who want to get the best of both worlds: both the vis sources of Hibernia and the correspondence and book trade of the continent.
What is plausible is entirely a question of how you want the infrastructure and economics of your saga to work. RAW explicitly leaves this to troupe decision. IIUC, the portals between Durenmar and the Domus Magnae are open to all, at 2pvf/magus. The portals to Harco OTOH are left much more to the discretion of the guardian and/or the SG. There are several such portals, but not clear than anybody but redcaps can use them.
New portals are not just a question of paying the cost including fair salaries to the few magi who are able to do the enchantments. House Mercere owns the portal and instates a guardian who is responsible, not only to prevent unwanted elements from using it, but also prevent anyone, even friendly magi, from studying the portal to be able to recreate the enchantment. Suitable guardians are rare, and there is nothing to say that House Mercere will allow a portal even if the tribunal unanimously decide that they want one. Again, there is no universal canon answer to whether it should be possible, but if it suits your plot, all you need is to design a perfect guardian, be they a covenant or a faerie queen ..
To me, this fits into Hibernia’s metaplot of “The Ordo Hibernia trying to resist being made to look more like the Order of Hermes.” A Mercere portal benefits so-called “English” covenants that want more and easier contact with the rest of Europe. Hibernian covenants used to doing things the Hibernian way don’t want that contact or influence. A Mercere portal leading from Europe to Hibernia makes it easy for young European magi to emigrate there, and that’s not what Hibernian covenants want. The benefits of a portal are largely lost on Hibernian covenants who, as pointed out, already have known methods for fast travel on an island where you can already get anywhere in a week.
So the covenants most eager for a portal will be those most hated by the majority of Hibernia: Ashenrise and Praesis. PCs may want a portal for all kinds of reasons that mean nothing to the Hibernian covenants they like (we want to adventure in other lands! And make a fortune as merchants!) and find their only allies in this venture are magi they’d otherwise dislike. Houses like Guernicus and Tremere—who want to “reform” Hibernia and see easier contact with Mythic Europe as a way to accomplish their goal, but whose magi are traditionally disliked and villainized—will support the PCs effort.
That’s a great recipe for story.