The idea for this fic came as I was actually writing another one. For some reason I am obsessed with the idea of why Sherlock uses his middle name instead of William- his given name, and what might have prompted him to change it. I have read a couple of fics that have kind of dabbled with the idea, but I decided to try my hand at why he might use Sherlock instead of William.

The first part is set about a month after John meets Sherlock and moves into Baker Street. The second part is set a short time after the end of "The Final Problem". After all the events at Sherrinford and Musgrave. I think this can be considered canon, as it doesn't change any details, really.

A letter arrives at 221B Baker Street addressed to a 'Mr. William Holmes'. John Watson wonders who this mysterious man might be. When he learns the truth, it ends up being much more than he bargained for.

88888888

Snow fell thick and heavy outside the tall windows of 221B Baker Street. A fire flickered and crackled in the fireplace. Sherlock Holmes looked rather comfortable lounging in his well worn black leather chair. Boneless, one would almost say. He had sunk so far into the material that it was hard to tell where it stopped and his black dressing gown began.

"No, don't get up. I'll go check our mail." John grumbled. There was no response at all from the tall detective. Apparently he was so deep in his mind palace that John might as well have been nonexistent.

He felt like that quite often.

John got up and stomped much louder than necessary down the stairs. He knew that it was rather petty, but he hoped that it took Sherlock out of his mind palace, even if only for a moment. They hadn't been flatmates for very long, and John appreciated that Sherlock was... unusual to say the least. But it took its toll on John to be routinely and alternately ignored and insulted. If he was honest with himself, he was starting to think that perhaps this wasn't the best of ideas. In for a penny, in for a pound, he reasoned with a shrug.

He got to the front door and sorted through the mail. There were a couple of letters for Mrs. Hudson. John put then on the little table right outside her door. As usual, there were bills, at least a couple were already overdue, which drew a long sigh from his lips.

But the last letter, he turned over in his hand a few times. There was no return address, but the postmark was from within London. The address was written out personally, it hadn't been printed onto the envelope. The address was correct, but it was address to a William Holmes, which puzzled him.

Up the stairs he went, trying to rack his brain over why there would be a letter addressed to someone with the same last name as Sherlock.

"Sherlock, do you have any other family members that I don't know about... any that might have lived here before you?"

Silence.

"There's a letter addressed to here, but it's to a different person named Holmes."

Silence.

John sighed and ran a hand down his face. "Sherlock, listen to me." His voice deepened and got louder. He was tired of this, and come hell or high water, he -WAS- going to get an answer.

"Do you know someone named William Holmes?"

Sherlock's eyes shot open. The previously steepled fingers went to the arms of his chair. In less than a heartbeat, he had pushed himself up from the chair and used his long legs to propel himself the couple of steps forward towards John. He grabbed the letter out of his hands and studied it.

"I'll take that as a yes." John mumbled and sunk into his chair. It was obvious that he wasn't going to get a response from Sherlock, but at least he could watch him study the letter.

Sherlock flipped it over in his hand a few times, examining it from every angle possible. "No return address. Postmark in London."

"I figured that out, genius." He mumbled. John was actually glad that Sherlock either hadn't' heard him, or had decided to ignore him- as usual.

"C4 envelope, ivory. " He turned it around a few times, put it up to his nose and sniffed it. "Very faint smell of sandalwood and..." He sniffed it again. "... Lemon. "

Whatever anger John had been building up slowly drained out of him. One would think that he would be tired of watching the man deduce, but it still never failed to amaze him. He was a master at his craft, there was no doubt about it.

"Kingsley Fountain pen... Eliot Chrome... no... Barley Doue. Left handed, so that narrows it down quite a bit."

Was it John's imagination, or did Sherlock actually cant his eyes up at him after he said that? He might be left handed, but so were 10% of the world's population. And he was still no closer to figuring out who William Holmes was.

The doctor cleared his throat, and was actually surprised that Sherlock looked up at him, acknowledging his existence. "Are... you going to open it?

Sherlock tossed the envelope onto the table beside him. "I already know what it is. Boring."

John had no idea how to respond to that. He started to say something, stopped, and then finally settled on "Would you care to tell me what's going on, then?"

"No."

He got up and grabbed his coat. "Never mind. I'm going out."

"There's a snow storm out there."

"I need some air."

Before Sherlock could answer, John threw on his coat and stomped down the stairs, leaving a rather unamused detective in his wake.

Xxxxxx

John stayed out as long as he could. He knew that it was a very long shot that Sherlock would actually be asleep when he got back. The man never slept. Maybe he would be lucky and he'd be in his room, but John very much doubted it. .

He walked until he couldn't feel his fingers or toes, and the snow was thick enough that it was seeping over the tops of his shoes and soaking his socks.

There was no use delaying the inevitable. He sighed and turned back towards Baker Street.

By the time he stepped through the door, he was shivering. He stumbled up the stairs, pulling his soaked jacket off as he went. John knew that he had stayed out too long, and now he was starting to feel the first hints of frostbite.

Surprisingly, Sherlock was not in the living room, but the fire was still roaring. He quickly pulled off his boots and socks, not surprised to see how pale and wet his toes were. Thankfully, they were still pink, so no frostbite damage. That was good. Next was his jumper and his pants, which were soaked at the bottom. That only left his shirt and boxers. Thankfully, they were dry enough that he decided he could leave them on.

He took a blanket from the couch and wrapped himself around it tight, sitting in front of the fire and letting it slowly warm his core. A cup of tea wold have been wonderful, he though to himself, but there was no way that he was going to move from this spot. He closed his eyes while his body slowly inched back to some semblance of normal.

It could have been 5 minutes or 15, he wasn't sure. He might have actually drifted off to sleep a bit. But finally he was starting to feel the warmth radiating through his extremities. John opened an eye and looked back to the table next to Sherlock's chair. The letter was still there. It looked like it hadn't moved since it had been tossed earlier.

There was no reason that he couldn't read it. If Sherlock really didn't care about it, he could just read it and then throw it away and it wouldn't matter because it was 'boring'. Right? Of course he knew as soon as he thought it, that idea was totally ludicrous. Sherlock had an eidetic memory, and he would know that the letter had mysteriously disappeared..

"This is really bothering you, isn't it?" John almost jumped out of his skin. His whole body tensed and he looked to the hallway, where Sherlock was standing, his arms crossed. John finally let out a breath that he didn't know he had been holding. He didn't answer, just gathered up the blanket that he was in and moved from the floor in front of the fire to his chair, where he flumped unceremoniously.

Sherlock flopped in his own chair and took the letter in his hand again, turning it over and around like one would twiddle a pen. He sighed. "Fine." He opened the letter, unfolded it, and started to read.

"Dear William. We regret to inform you that your great uncle Alastair has passed away. As a part of his will, he has left you a set of sabers from Iraq. Please respond to this letter within 30 business days with the confirmation of your address, and the sabers will be shipped to you. Hoping this letter finds you well, Robert Smythe. Williams and Roberts Attorneys at Law." He put the letter down. "There. Are you happy now, John?"

"You.. knew you were getting sabers?"

Sherlock gave him an incredulous look, and then, to his surprise, chuckled. "I could tell it was some sort of will reading. I have gotten these letters before." John wanted to ask about that, about how many people in his family had died and left him things, but he kept that query to himself.

"So... that means... your name is not Sherlock."

"It most certainly is."

"But the letter said William."

"You have more than one name, correct?"

"So, William is your middle name then?"

Sherlock sighed and closed his eyes. "Please, do try to keep up."

"William... is your first name."

Sherlock opened his eyes. "My blogger does learn." He smirked.

"Sherlock is your... middle name."

"Yes." He said in an exasperated tone.

"Hmm."

"Hmm?"

"Well, I'd like to ask you why you decided to use your middle name instead of your first, but I am sure that I wouldn't get an answer."

There was a flash of... something.. behind Sherlock's eyes.. Was it... pain? John wasn't sure.

"No. You won't." Sherlock got up and walked to his bedroom. "Good night, John." The rather loud slam of his bedroom door left little room for argument.

John sighed. "Good job, Watson." He got up, abandoning the blanket to the chair, and headed to his own room. At least this nightmare night would be over.

Xxxxx

"You asked why I call myself Sherlock, and not William."

"What?"

"A month after you moved in. You were going through the mail, and there was a letter from a lawyer stating that I had been a beneficiary in a will reading."

John scoffed. "Are... you kidding me, Sherlock? That was 6 YEARS ago!" He shook his head and laughed. "You are seriously about to continue a conversation we started 6 years ago.

"Well, if you don't want to know..." The detective shrugged.

Of course he wanted to know. Damnit, he'd been wondering since they had had that conversation, but Sherlock had not handled it well, so he had never brought it up again. John sighed. There was no other way to do it, he had to play Sherlock's game. "Okay, so, why did you start calling yourself Sherlock?"

Sherlock let out a deep breath, steepled his fingers, and then began.

"Since you know about Eurus now, I can tell you the story. When you asked me the first time... If I had answered you, I would have told you it was because I was so distraught that my dog had died that I was tired of everyone calling me William. It just reminded me of Redbeard. That sounds like a silly reason to change a name- because a dog died. Even in my own mind, it seemed rather ridiculous, and I thought that perhaps there was something else to it. I scoured my mind palace and could find nothing else. Those memories. I had them buried very deep." He paused for a moment.

"Of course, now I know better. Those memories, as painful as they were, have been unlocked. Now I know the true reason. My friend, Victor and I. We were inseparable as children. He lived next door, though that is a relative term given the size of the estate. He would walk the kilometer to my house and stay all day."His voice dropped a bit and he closed his eyes.

"We called each other 'Redbeard' and "Yellowbeard', but when we were not pirates, I was William and he was Victor. When I realized that she had..." his voice broke only the slightest bit.. "...That he was dead, there was nothing but sadness associated with that name."

"Despite what it might seem now, I very much looked up to Mycroft when I was a child. I admired him and strived to be like him. I liked that he had an unusual name. I had never really thought much about my full name before that. It was reserved for the times when I did something wrong. My mother loved to use my full name when I got in trouble"

"The more I thought about Sherlock though, the more I liked it, and the more I figured that it suited me. I was already unusual, other than Victor I had no friends. I wasn't popular in school because I was smarter than the teachers. So an unusual name would go well with an unusual boy, I figured."

That hurt John deeply. Sherlock already knew by the age of 5 that he was different and he would never fit in with the other kids, that he was always going to be an outcast of society, because he had such a brilliant mind. Kids were cruel, he had seen it first hand. They figured that the best way to handle something you didn't know or understand was to bully it into submission. He had never told Sherlock, but that was why he had gone into both the Army and medicine. To defend himself, and to help others. Of course, Sherlock was brilliant. John reasoned that he had probably already figured that out for himself.

"So I told my family. It took some time, and mistakes were made, but they took to the new name pretty quickly. Unfortunately, school was not as easy. The teachers were slower to catch on, and of course the kids understood this as more leverage to be used against me. By the next year though, the teachers only knew me as Sherlock, and the same with the children, so it wasn't as bad."

Sherlock finally opened his eyes, and put his hands up quirking a little smile. "That's why."

"Did... you ever entertain the notion of using Scott?"

Sherlock made a disgusted face. "No. I hate that name."

"Why?"

"Do I really look like a Scott?"

"Do you really look like a William?"

"More than Scott."

John wordlessly conceded the point. "Perhaps." He smiled. "But to me, you will always be Sherlock."

Sherlock smiled warmly at him. Sadly, the moment was broken a second later when the baby monitor went off.

"Crap. I'll go get her. It's past time for her feeding anyways." John smiled back and headed upstairs where Rosie was sleeping in his old bedroom. His mind was racing a mile a minute as he climbed those stairs. John was quite aware that it had taken a lot of trust to tell him the story, and he felt humbled that Sherlock had trusted him enough to give him some very personal insight into his life.

They had both literally just been through hell and back at Sherrinford, and neither of them had quite fully recovered yet. It was going to take time. But this was a good way for the healing to begin.