That's quite the devious plan there; it's always best to not face the Theodosian walls head-on but just bypass them. It would be very risky to send Pepin in for the assault but, if it succeeds, it would be a great boost to his public profile.
OOC: Funny you should mention...
IC:
The Next Morn,
Down they went into the darkness of that disused old sewer path, their way lit only by the torch Berenger carried. The four men, or rather three men and one on the cusp of manhood, the Prince of Francia, Pepin Karling, carried their way in relative silence, the full enormity and difficulty of their task now firmly settling itself upon them.
They had now only to do their part, and act in the hopes that the other elements of Karloman’s plan came to fruition as well. If the Venetians were too late… or the army outside the city was not able to cause enough of a ruckus at the walls… or one sentry from Galata happened to gaze in the wrong direction at the wrong moment…
Pepin swallowed, and forced the doubts from his mind. All war was a risk, his father had said, and the only way to know for sure which ones were right was to take the ones you liked and see who won out in the hand. Only God, and fortune, and the actions of himself and these three men in the tunnel here with him, could decide the fate of the siege now…
On and on they went, forced to their hands and knees in some sections, as the crumbling sewer tunnel became too small for a fully upright man to walk through. Only the light of Berenger’s torch guided them through the dankest, darkest pits of the disused tunnel through which they traversed.
One more step… and then another… and then another, flinching at the sound of a stick breaking beneath a man’s boot… relaxing as it becomes obvious it was one of their own retinue… forward again… flinching at a shadow here… and then another step…
On and on and on…
The Golden Horn, Constantinople
At dawn, the drums began to sound, booming over the waves of the Bosphorus that lapped against the shores of Constantinopolis.
The Venetian ships had come.
Approximately two hundred vessels, crewed by some of the finest captains and crews throughout the Mediterranean had answered Karloman’s call… and his purse, for the hiring of such men was not an inexpensive endeavour.
But the men of Constantinople were ready for them. The Golden Horn would be protected at all costs, and the city’s vital sea supply line would remain under Greek control. The drums ceased…
The ships of Byzantium lobbed their first volley.. Large jars were thrown towards the Venetian ships…
The first jar ignited with a boom that jarred the ears and split the sky like a thunderclap as it tore through that too easily flammable wooden hull...
The use of Greek Fire at the Siege of Constantinople in 783 tore through many of the Venetian Ships. Depicted is an artists reconstruction of the detonation of the flame.
Entire ships and crews disappeared in a burst of fire that spread across the water, rapidly expanding outward, the timber of the wooden ship’s hull being the kindling that ignited the waters of the Golden Horn…
But not enough Venetian ships were caught in the first blast for it too be over that easily…
Walls of Constantinople, landward side.
“Movement!”
Strategos Maximos’s head snapped around to where the shout had come from.
The soldier who had called had been right, the Franks land force outside the walls were on the move. Clearly they intended to coordinate the Venetian assault on the Horn with a large-scale assault upon the walls.
Shouts emerged, as a group of Frankish men were seen breaking from their formation. Together they held a large, wooden object that had been hammered together over several weeks. On the outside of the little group, they were shielded by a group of heavily-armoured individuals, who raised their shields over the heads of the men carrying the flat wooden object to cover them from arrows or projectiles…
The purpose of that flat wooden beam became abundantly clear to a horrified Maximos as the men ran towards the ditch before the city walls… and began laying the flat beam down over the top of it…
“Set it alight! Set it alight!” he screamed, and the men atop the wall scrambled to find flammable materials to set the tips of their arrows alight…
While they scrambled, a group of sappers began making their way to the city walls from the Frankish lines, now with a clear line of movement due to the wooden beam that formed a bridge right over the defensive ditch.
The first ignited arrows began to fire, they struck the beam, but then the flames sputtered and died…
Watching from afar, Karloman could not suppress a satisfied smile.
“Now you see why we had the planks soaked with water before we started this morning?” Karloman asked “If they try to set it alight, the flames will douse themselves out before they have any chance to burn the bridge.
“And the ladders, sovereign?”
“Yes yes,” Karloman gestured impatiently, “Start sending them forward now as well, the more attention we draw off the Venetians… and away from Galata, the better.”
Galata, Constantinople
The tunnel seemed to stretch on. One foot in front of the hour, for another hour.
And then… the light went out.
A banging sound suddenly was heard ahead of Pepin. He rushed forward, confident he knew what it was.
Berenger was banging his fists on the walls, face streaked with sweat, eyes widened with wild panic.
“The light!” He hissed, “The light went out!”
“Keep it down or they’ll hear,” Pepin half-whispered and half-shouted, trying to grab Berenger’s wrists before they pounded the wall again, “Get that torch lit again!” he snapped, as one of the men scrambled for the torch the panicked Berenger had discarded.
“Quiet!” he snarled again, as Berenger began to whimper loudly.
Hands shaking finally sparked the torch again, Berenger’s breath began to rattle harshly, and Pepin realised his hands were hurting from how hard he’d been gripping the man’s shoulders.
“Pass it to me,” he commanded.
The torch came to his hands. He thrust his arm under Berenger’s shoulder and pulled, hard.
“Come on!” he insisted, and began to drag the panicking man further forward. Though he noted he looked less crazed now the torch had returned.
Further and further they went, but Pepin’s companions had began to notice the marks that were leading them close to their destination.
“You hear that Berenger?” he asked his stricken friend, “We’re nearly there.”
“Pepin…” the man licked his lips, as though he were a parched man dying in the desert, “I’m sorry, the light… confined corridors… I’ve never dealt well with them.”
“It doesn’t matter now,” Pepin replied brusquely, “We’ll be out of here soon. Are you fit to fight?”
“I will be,” Berenger replied, and Pepin noted with relief that a little strength had come back into his voice, and his face was beginning to look less pale.
“Good, because we may have to.”
They strode a few more metres, Pepin realising his arms were burning from the weight of pulling Berenger along.
“I’m fine now little Prince,” Berenger replied, “You may release your grip.”
Pepin did so, suddenly realising just how tired he felt. Berenger stumbled slightly, but then managed to steady himself.
“This is our exit.”
One of the men was gesticulating to a small causeway just a few metres ahead, and from there… they had a clean route into the suburb.
“Ready?” Pepin asked,
“Aye,” Berenger replied, giving a strained smile. “Ready.”
And up they went…
The Battle of the Golden Horn.
The naval battle as it was proved messy and chaotic, individual boarding actions and the ramming of triremes alike sunk over a dozen vessels, but no decisive victory was won within those waters. The Venetians knew full well that so long as Galata was taken, the enemy would lose their main port of safe harbour and re-supply, and the main city on the south side of the Horn could then be blockaded with impunity.
The fighting nonetheless continued for two hours, the amount of time Karloman had told the Venetians they needed to continue the fight before beginning to withdraw. The signal went up, and the ships began to pull back, short several dozen of their best vessels and a couple of hundred sailors.
But if the Greeks cheered this seeming victory, the joy would soon turn to fear and dust when what awaited them at home became clear…
Galata
After the tension and difficulty of the trip through that long dark tunnel, the route through Galata proved surprisingly simple. Dressed in ordinary civilian clothing, and hurriedly making their way towards the gates, the four Frankish men arrived unimpeded to their destination, the northern-most gate that blocked the Franks from access through Galata’s wall.
“Through here!” Berenger hissed, directing them through a sturdy wooden door that obviously served as a guard tower and barracks. “They’ll have a mechanism to open it up in here!”
The four arrived, and after a few moments of searching, Berenger found it.
Just as it was pulled, the door burst open.
“Anfred, do you ha- what? Guar-!” the Greek soldier’s cry for help was cut off as one of Berenger’s burly compatriots slashed him across his throat, reducing his vocals to blood-soaked burbling as he pitched forward.
“Don’t look child,” Berenger told Pepin quietly, who had seen the exchange.
“I appreciate the thought captain, but I am no child.”
As the gate opened up and the four men began to grin as they saw their task complete, only Berenger turned to face the son of Emperor Karloman with a wearied gaze.
“No, I suppose you’re not, are you?”
Then he smiled, and hugged the boy firmly…
The fall of Galata was swift and sure after that. The opening of the northern gates brought the Frankish forces into the suburb, at which point they overwhelmed the surprised garrison, who were outnumbered, and whose focus had been directed towards the river in case the Venetian ships had breached the Horn…
And when the Greek ships returned to port, it was their own turn to be set ablaze, as the Franks overturned caches of Greek fire into their own ships, or rained flaming arrows down upon the wooden hulls of those triereme’s whose bronze rams were so devastating below the water.
By evening, the orange glow of dusk was amplified by the burning waters of the Golden Horn, but Galata had fallen, the Venetians now occupied the Horn, and their ships were moving into the Galatan docks while others blockaded the mouthof the river… and the first major obstacle to the fall of Constantinople was gone…
OOC: So... yeah, a costly victory in terms of ships, but Galata now in Frankish hands and the enemy firmly blockaded. Not to mention Pepin saved the day when the claustrophobic Berenger started to freak out.
I took some inspiration in the writing of this from a bunch of sources. Obviously the Byzantines used Greek fire a lot, but it's use as a way to destroy enemy ships was very common. The decision to target Galata first before striking at the city itself is based on the Crusaders siege tactics in the Fourth Crusade in 1204, though the method by which it falls is different. Constantinople was an ancient city and it's water and aqueduct systems were extensive, as was it's sewer systems. It would not have been beyond the realm of possibility that some disused element of it could've been used to travel the city secretly, or at least parts of it, but obviously the specific entrance I use here is fictional. But what can I say? Real medieval sieges were mostly very boring and don't make great story fair unless you spice them up a bit, so I did!