A Marienburg mercantile concern which made its original money brokering iron ore and metal from the Isrillion mines. Their contact with the Order through Marienburg’s ranking Procopian (my notes say only, “a disreputable individual whom we must name,”) led them to diversify into international trade, with a focus on the Dawn; as Isrillion’s mines faltered, Malthus & Liebengrab came to lean more and more upon that trade, until it comprised the majority of their business, leaving them with a wealthy and exclusive but rather small clientele. The firm does well, and is even prosperous, but is firmly in the middle rank of Marienburg merchants, with no exclusive ducal appointments—much less princely.
The head of the Malthus family died some years ago, leaving to the Liebengrabs those shares that might have gone to his ne’er-do-well son, a notorious gambler who has turned to pimping and fencing to keep himself in his accustomed manner. Malthus also had a daughter, who married minor Tyrrian nobility 10 years or so ago. Liebengrab pays a generous pension to Malthus’ widow.
Johannes Liebengrab is therefore quite interested in a possible ressurection of the Isrillion mines, and is willing to defray half the costs of hiring a surveyor to assess their condition.

As of 421 or so, I should say.
From notes for a trip to Marienburg game. —The Isrillion party would have arrived to find that Liebengrab had just died; that Timos, an orphan adopted some years ago by the childless Liebengrabs, was doing his best to run the merchant-house; that Timos had the help of one Counsellor Stavrik, who had for many years assisted the Widow Malthus in her charity work, and whose scruples were rather less evolved than his intentions; that Counsellor Stavrik was suspicious of unwholesome Dawnish trade, but as it made buckets of money, was willing to keep a close eye on its continuation; that the said Counsellor was also suspicious of anything to do with Isrillion, as they were affiliated with the aforementioned Procopian, a disreputable fellow, and as their mines were not currently making any money, much less bucketfuls, was much less well-disposed toward renewing any relationship whatsoever with the covenant, no matter what eager promises Liebengrab might have made; and that Ashley Malthus, the ne’er-do-well, was interested in playing to the hilt whatever games might prove necessary to secure his rightful share of the merchant-house.
But I’m not wed to all that. And it might prove a complicated distraction. So I’m leaving it non-canonically in the comments for now, so to speak.