Very well. The B.L.C.A. or 'Blica', as it is nicknamed, is a law that was passed as more and more Pureblood Wizarding families died out, or as in the case of House Prewett as a result of Voldemort's War, extinct in the male line." Rockclaw started, "As most Pureblood families are interrelated to some degree or other, it was and is quite possible for a single person to become Family Heads of different bloodline simultaneously, this law states that any wizard who is in line to become head of three or more Houses are to marry one witch for every bloodline that he is due to inherit."
Harry gaped at Rockclaw in shock as the Goblin continued to speak.
"Now, as the Wizarding World has borrowed from a fair few pieces of Muggle legislation, it is technically illegal to marry more than one person at the same time. The sole exception is, of course, a person under the aegis of this law."
Rockclaw regarded the young man sitting as if petrified on his seat. The look he wore on his face was a mix between horror, bewilderment, incredulity and disbelief. Quite understandable, considering the boy is Muggle-raised, Rockclaw considered.
"Is…is there no way to get out of it?" Harry asked at last, "This is…I just…"
He seemed to be driven to near incomprehensibility by his shock, making Rockclaw chuckle.
"I'm afraid not, Mr. Potter. The law is ancient, going back to shortly after the founding of Hogwarts, to the time of the wizard Merlin or Myrddin if you prefer the Welsh version. It was his spells and enchantments, his magic that bound this law to the Sovereignty Magic of Magical Britain." Rockclaw informed Harry soberly, "The only way that you could escape it is to destroy the Sovereignty Magic itself, which is…inadvisable in the extreme."
Harry slumped down in his chair, defeated by the Goblin's words, his mind racing at the ramifications for him that the two laws combined entailed.
"Now, there are a number of deadlines and safeguards on the law to ensure your compliance." Rockclaw continued once Harry had recovered himself somewhat, "The deadlines are thus: First, you must at least be engaged to marry three witches by your seventeenth birthday. Second, by the time you reach your twenty-first birthday, you must be married to all three.
Should you not meet the first deadline, magic will inform the Wizengamot, who will assign you witches as your wives. As most of the Wizengamot are of the old, Pureblood families, it is doubtless that some of them are former Voldemort supporters, meaning you will have to be on guard day and night for fear of assassinations, mind control and manipulations."
"So, you're basically telling me that either I choose my wives myself or I'll be marrying a nest of snakes?" Harry asked, reasonably certain that he was correct.
"Almost certainly, Mr Potter." Rockclaw replied, "Most of the, shall we say, questionable, members of the Wizengamot are former members of Slytherin House. Unfortunately, the second Law is not subjected to the Fidelius Charm, so the Ministry no-doubt already knows about it as well."
"Hang on!" Harry said in alarm, "If the Charm is working properly, then why did the second Law kick in?"
"The magic interwoven into the laws by Merlin is one of the finest examples of Wizarding spellcasting in existence, Mr Potter." Rockclaw informed him, "Any Charm has a weakness and Merlin anticipated the Fidelius Charm when he cast his spells. It is said that somewhere in Britain is Merlin's Keystone, his direct link into Britain's Sovereignty Magic. It supposedly allows the user to alter the very fabric of the spells governing the Sovereignty Magic. Merlin made all the ancient laws immune to a Fidelius Charm cast by pure magic or in other words, by themselves. A very tricky bit of spellwork beyond any living witch or wizard today."
Harry took this in as par for the course. "So…what do you suggest I do then?" he asked, "I can't imagine any girl willing to share a single guy with two other girls!"
'Ah, to be young again.' Rockclaw thought wistfully. He had a mate he had taken back in his younger days and he had never been happier.
"Well now, that just depends on the person, Mr Potter." the Goblin said expansively, "Unfortunately, there are the different Family rules to do with marriage to consider as well."
"Now what?" Harry groaned.
"Each House has…rules that dictate who you may or may not marry." Rockclaw explained, "I am fairly certain that you can guess a condition of marrying into Slytherin's House, can you not?"
"She has to be a Pureblood." Harry recited dully.
"Just so." Rockclaw said, "Other than that, the only consideration is that she be a virgin until her wedding night."
Harry flushed red at the bluntness of the Goblin's reference, to which Rockclaw paid no mind and flicked through the portfolio in his hands.
"Moving on, the Peverell Family has surprisingly few conditions as well, only specifying that the witch in question be magically powerful, that she not have 'unsightly blemishes upon her countenance' -that's bad spots or boils on her face to me and you- as well as that her family being at least an Ancient House, so Pureblood again, I'm afraid."
"Of course." Harry sighed, "Come on; hit me with the final blow. What conditions do the Potter Family have?"
"Just the one: that you love her." Rockclaw gave a toothy Goblin smile at Harry's surprise, "The Potter Family was always one of the more liberal and forward thinking families, similar to the Ancient House of Weasley."
"Can I ask about these…Houses you keep speak of?" Harry asked, "I have no idea who is in what position."
"Ah, well, that is rather easy." Rockclaw said with a smile, "At the bottom, you have regular pureblood families that have either been cast out of their families and disinherited or have left them for philosophical differences, muggleborn families and squibs.