Anna was five when she came up with her first plan to coax Elsa out of her room.
It wasn't a terribly sophisticated one; it consisted of placing a sweet pastry (wheedled from the kitchens) outside the door and then waiting for Elsa to open up.
Unfortunately, Anna forgot about the plan on her way upstairs from the kitchen and ate the pastry herself.
The second attempt was when she was five-and-a-half.
This time, she slipped a carefully-printed invitation to a 'Snowman Ball' under Elsa's door. She had supposed it was foolproof; after all, Anna had been careful to mention all the fun winter activities and food and chocolate (a week's worth of dessert saved up) at the ball.
The door had remained obstinately closed. Anna was disappointed, but the prospect of all the chocolate now for her went some way towards improving her mood.
The resulting sugar-fuelled rampage around the castle was still recalled by the servants, often with a shudder.
A stubborn six-year-old Anna decided that luring was too childish a tactic, and opted for waiting.
She planned her venture meticulously; a blanket, her favourite Anna and Elsa dolls, some snacks for when she was hungry, a mug for drinking, and a book to read when she got bored.
Anna set up camp outside the door using her toys and draping the blanket over to make a very cosy tent. Pleased with her work, she ate her snacks and then curled up with her book.
She lasted about ten minutes before falling asleep, and was carried back to her room by her father.
Seven-year-old Anna tried a method that usually worked for her – bribery.
"Happy birthday, Elsa!" called the younger princess excitedly.
"Thank you, Anna."
"I brought you a present, but you gotta open the door so I can give it to you."
There was a pause. "Thank you Anna, but you really didn't need to get me anything."
"Of course I do. Now open the door so you can see."
"It's fine. Can you give it to Mama or Papa? I'm busy right now."
Anna pouted. "But they're busy with royal stuff. So are the servants."
A pointed silence descended.
There was a rush of air from behind the door. "No, Anna. I'm sorry."
Anna burst into tears and ran back to her room to sob herself to sleep.
The next morning, she woke up to find a neat little note on her pillow thanking her for the birthday present. Or to be precise, it had probably been placed on her pillow earlier but through all Anna's nighttime tossing and turning, she found it stuffed down the front of her nightgown.
That went into a large chest Anna took to calling, 'The Elsa Collection'.
When Anna was eight, she decided to try another tack.
The new servant girl Ingrid – hired to replace one of the older serving maids – was quite friendly to the lonely princess and readily agreed to help out with her plan.
With a laundry basket in hand, the servant girl knocked on Elsa's door.
"Your Highness? I've come to collect the laundry."
There was a pause, and the door clicked open.
"Aha!" screeched Anna, leaping from behind Ingrid's skirts and making a desperate dash for the door.
Elsa was quicker, and slammed the door shut – an instant before Anna could rush in, and she crashed feet-first into the unforgiving wood.
"Elsaaa!" she growled, rubbing both feet.
A few weeks after Anna's ninth birthday, she decided to try negotiation. It was a sophisticated tactic that Joan had suggested while Anna was in deep discussion with the other portraits.
Wearing her best dress, she marched to Elsa's door and knocked solemnly.
"Princess Elsa of Arendelle? It is I – Princess Anna of Arendelle." She swept a deep curtsey. "I respectfully request your presence for a – social event."
The door remained silent.
Anna cleared her throat. "Princess Elsa? You have to acknowledge me – look, I have a diplomatic banner!" The scribbled-on bedsheet was duly presented and an attempt made at stuffing it under the door. "This means you have to listen to what I say. Unless you desire war between our kingdoms!"
There was a muffled sigh. "Anna," said the voice, "go away."
"This… is an insult!" Anna puffed up her chest. "This is tanta – tanta – tentacle – to a declaration of war!"
Which was why an hour later, the castle butler Kai found Anna dressed up in bedsheet armour and leading an army of toys into battle against Elsa's door, valiantly hacking away at the paint with a wooden spoon.
Ten-year-old Anna dashed from the library, inspired by stories of jousting knights. Borrowing a broom from the kitchen staff, a roll of twine from the castle gardener, and a gauntlet from the suit of armour downstairs (it was fine if she returned it later), she turned the brand-new bicycle she got for her birthday into an impressive battering ram.
"Charge!" yelled the younger princess, pedaling at full speed down the hallway.
Well, it was a gross mistake on the castle architect's part to place Elsa's room right next to the grand spiral staircase.
Or so Anna kept telling anyone who would listen while she waited for her broken arm to heal.
Elsa's response had been a painstakingly drawn and coloured-in picture of Anna in armour, perched on the back of a reindeer. It immediately went into the Elsa Collection.
The tiny sign of acknowledgement meant that her efforts were working!
At eleven years of age, Anna decided that those methods were far too passive. She'd been reading about the adventures of Aladdin, Flynn Rider, and their swashbuckling stories of adventure and was inspired.
She would simply break in.
And if the door was impervious to her efforts – there was always the window!
Tying a rope (she borrowed a coil from the gardener, who turned out was a Flynn Rider fan too) securely around her waist, Anna tied the other end to the weathervane and positioned herself above Elsa's room window. Like Flynn, she would swing down and crash feet-first through the glass. Then, she'd cut the rope with the knife hanging at her waist.
Unfortunately, the weight of an eleven-years-and-two-months-old girl small for her age wasn't enough to break the window panes; Anna bounced off the glass, spun around crazily, and remained suspended outside for half an hour until the castle gardener came to get her down.
That day, Anna learned that even a royal princess (second in line to the throne) wasn't above a good spanking.
At the very least she had caught a glimpse of Elsa. Or at any rate, a blonde-haired blur that got up and ran for help when Anna attempted to break down her window.
The next morning, Anna found a little note asking if she was alright that looked like it had been slipped under her door in the middle of the night.
It was also a little damp at the edges like it had been frosted and then thawed but Anna didn't care. It joined the other trinkets in the chest.
Shortly after turning thirteen Anna had had enough. She marched to Elsa's door and knocked loudly.
"Elsa! Open up right this minute or I'm going to break this door down!"
"Didn't you already try?" came the amused reply.
"El – saa," whined the younger princess, "come on… we used to be best friends! What happened? Was it something I did? You can talk to me. Please?"
"You didn't do anything," said the voice quickly, and then paused. "Maybe we can talk another time, Anna."
"Can't we talk now?"
"No, we can't – I'm busy, I have to study…"
Anna harrumphed and tried to peek through the keyhole – only to jump back with a shriek. "Your keyhole's all frozen up!"
"Oh. Yes. Sorry Anna – but you should go now."
"Fine." She stalked away to her room, muttering under her breath about annoying older sisters that stayed in their rooms all the time.
Later, she slipped a drawing of ogre-Elsa sulking in a cave under her sister's door.
Two days later, she received an unflattering portrait of herself dangling unceremoniously from a rope outside a castle window from Gerda.
"This means war," she growled. But she was careful to slip the drawing into the wooden chest first.
Her next effort was a crudely-drawn stick-Elsa and stick-Anna comic strip that mostly consisted of unbecoming language learned from the servants and stick-Elsa's gruesome fate at the hands of icebergs, icicles, and snow monsters in turn.
Elsa's response (delivered via a bemused Kai) was a letter chiding her for her colourful language – and a cartoon-Elsa eating handfuls of chocolate labeled 'Anna's chocolate'.
By the time she was fourteen, Anna had given up on getting Elsa to open the door; rather, she was treating the door like her sister. It wasn't such a huge jump, given that she had grown up with her face pressed to it.
"Hi, Elsa," said Anna, leaning back against the cool wood. "I had a really, really tiring day today. You wanna hear what happened?"
"You do? Really? Okay. Well, Mama and Papa had me start dancing lessons. Dancing. Me. Mama said it'll make me more graceful, which doesn't make sense, since Papa said once I haven't a graceful bone in my body, so how can I be more graceful if I'm not graceful in the first place?"
"Anyway, I ended up trampling on the dance master's feet, tripping over my own gown, and hitting Papa in the face when I tried to pirouette." Anna sighed heavily. "The dance master said a lot of things that sounded like French and they forbade me from repeating them ever again."
"I bet you can dance really, really well, right, Elsa? I knew it. You have plenty of grace. You probably have grace oozing out of your fingertips."
"The tutors said a princess has to have poise and grace and dignity. I don't think I have any of them," Anna mumbled. "Good thing you're the one who's gonna be queen, right Elsa?"
The younger princess got to her feet, brushing dust off the back of her gown. "Well, I gotta go now. Nice talking to you, Elsa."
The door squeaked as she walked away. Anna froze.
A blonde head peeped from the ajar door; startlingly blue eyes the colour of ice stared shyly at her.
"I trip over my dress going down staircases," said Elsa slowly, "and sometimes I snort when I laugh."
"No!" said Anna with a little wail of laughter.
"Yes!" The door opened a little wider. "And one time when Papa and Mama made me attend a fancy state banquet? I couldn't stop giggling because this baron kept picking his nose when he thought no one was looking."
Anna approached the door reverently, as though afraid to come near the sister she almost didn't have. Elsa smiled nervously at her, her hands behind her back.
"… wanna build a snowman?"
Elsa's glance darted to Anna's; she fervently tried to project as much hopefulness as she possibly could.
They only made it as far as half a snow lump in the front yard before Elsa remembered that she had to go back and finish some homework but Anna didn't care.
It was still the best day ever.