Despite the many visitors in this thread, I drafted our final spoiler. Please comment and amend.
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The team (Furiey, Renata, Keath, Sabre, tao, Tone) had agreed to go for The Great Library and we completed it in 1000BC in the city named "Great Library". Stopped research gave us lots of cash from then on. Great Library afterwards built the Forbidden Palace (completed 510BC) and corruption dropped. We never moved the Palace to developed a second core, since Great Leaders came too late.
We built the following infrastructure: 2 markets, 2 courthouses, 2 aqueducts, 1 temple, 1 harbor. And of course some libraries, mostly for territory expansion, but in the core for research on chivalry (see below).
Monarchy came from the GLib in 430BC and we needed 6 turns of anarchy for the switch.
Worth mentioning is that we actively went for contact with America and Scandinavia, since they just didn't show up. Our galley contacted the Vikings 150AD and traded for the world map and American contact.
The occasional landings at Al Bait continued, but all invaders were bombarded and killed same turn.
We had some discussion on whether to research feudalism in the Middle Ages but stuck with a lone scientist on engineering. However, once the GLib gave us feudalism in 260AD, we abandoned (after 34 turns) this aproach and start full speed on chivalry due in 6 at 100% and -90gpt. This switch was also heavily motivated by the idea to finally get a Great Leader and - after capturing Zimbabwe with Hanging Gardens - hurry Sun Tzu's to start our Golden Age. And it worked beautifully. Great Leader Orhan appeared 280AD, Sun Tzu's was built 290AD, Golden Age started 300AD, and chivalry was learned 310AD. We stopped research forever and had +222gpt for upgrades.
In the fightings, the AIs were surprisingly weak (no SOD counter attacks) and it mostly was a question of troop movement to walk over them. In the end, the main problem was logistics and getting settlers to fill the gaps. 6 galleys went north to capture isolated towns and that pushed us over the domination limit in 520AD - announced in 530AD.
The rapid progress is shown in the following map sequence.