How to weaken the Byzantine Empire?

[alex]

I'm the King of Sicily right now and Byzantium is getting bigger and bigger with no one stopping them, which is making it harder for me to expand.

What is the best way to make them weaker so I can expand a little more?

I'm thinking it might be a good idea to swear fealty to them and then conquer their vassals from the inside and later lead an independence faction. But I could also swear fealty to the HRE for protection. Or I could try to conquer northern Africa to hopefully get more taxes and levies.

Could I get some tips on what to do next?

[Germaine's Bra]

Depends on the Era. I have less an issue with them being offensive than Alba running amuck invading everything and it's uncle.

[GorishiDan]

I'd swear fealty to them and try to destroy them from the inside. That would be a nice challenge too. I usually play intrigue and fabricate a hook on someone close to whoever sits in the throne, their kids, spouse, or if lucky, spymaster. And then murder then. Specially when the next successor is like a 6yo so vassals will be mad. Get the claim throne perk, execute it and then wait for an unfortunate change in the throne (such as a child) then get a claimant faction going. Most vassals will join you and lend their levies for the cause. Thats how i did it once. The only diff is that i started the game as a vassal in the byzantine empire. I didn't came from the outside.

[Rave Pathfinder.]

Weed out the strong leaders and incite disaray within its vassals.
just dont get caught .

[Madvaug]

Don't fight them, marry them =) Get some dynasty members with claims on Byzantine Empire (may take several generations), push their claims and see Empire burn. Later on you may claim your dynasty member's title for yourself, if needed.

[Iriath Zhul]

I neutered them by using schemes to marry my nephew to the empress-elect and then put her on the throne. That leverage let me put the future emperor as my ward, meaning I converted his faith and had future house leverage. When he ascended to the throne he was immediately assaulted by his Orthodox vassals, and I was able to get involved and help the great purge of Byzantium.

Now Byzantium is much weaker, easily cowed, and giving me a tidy 2 renown per month.