@ Iggy: that's pure bad luck
very irritating if they attack a city building a wonder
@ Own: that's why I love legios, they act as Pikemen and Swordsmen. 3-3-1 is superb for both attack and defense, add 50% defense bonus of walls and 20% (20?) if fortified, and they become the most feared defenders of the whole Ancient Era (although historically they have been mostly excellent attackers).
And surely LUCK is what helped me really a lot - if I had ZULUS near my boundaries I had to keep one legio on each city - 2 tile moving Impis are so damn irritating.
Update:
1560 AD: A stack of Legios, 1 catapult and Medieval Infantry siege Memphis, waiting 4 turns for Chivalry Tech to end.
Map Time... the big, red empire is mine
while that gray which fills the other big island is the Zulu colour - they conquered the English on 1555 AD. Funny thing is, the English had two cities which included 3 resources of Furs and 1 of Iron. No one of these resources was linked with a city, not even the two cities were linked. Smart Elizabeth.
1610 AD: The city of Memphis, after a long siege, falls in my hands. Utilizing a catapult, 2 medieval infantries and the Army I killed 5 evil pikemen guarding the city. The hardest siege. And now Thebes...
1620 AD: My first assault beg--CRAP! What are those 2 pikemen doing near Antium? Damn I have no defense to bring there - they are taking a city and I can just see.
1625: I retake the city and I notice Heroic Epic is not here. I need to rebuild it from scratch.
1690: RNG seems to have turned to my side, at least for a turn. 3 spearmen killed with 3 legios and my army, all redlined. War weariness has entered his catastrophic level - I must CONQUER that city!
And I complete Leonardo's Workshop.
1700: Hammurabi sends ridiculous spearmen and bowmen to 'siege' Antium. War!
Totally unexpectedly, I get another leader! Leaders come when you don't even think to them.
1705: I hurry Sistine Chapel. Babylonians make the city-state of India declare war on me. Bah.
1725: Peace with Hammurabi. Indian troops still camp around many of my northern cities and they provide a lot of trouble.
No more now. Peace with Gandhi. 3 gold per turn.
1730: I complete AGAIN the Heroic Epic.
1735: But it gives me the nice gift of another Leader.
1740 140 YEARS of SIEGE to conquer Thebes!! 10-15 spearmen killed one by one by a mix of legios, knights and medieval infantry!
Peace treaty with Cleo - 4 gold...
EDIT: lol Ansarking you posted when I was still posting this... it took me damn a lot to report the whole action