Saduleon
From A Wiki of Ice and Fire
The Saduleon is a great cog. It is owned by Illyrio Mopatis.
Recent Events
A Clash of Kings
Magister Illyrio sent the Saduleon, Joso's Prank and the Summer Sun to Qarth to bring Daenerys Targaryen back to Pentos in preparation for her return to Westeros.
A Storm of Swords
It was renamed the Balerion by Daenerys Targaryen when they set sail out of Qarth.