When a player loses his last town on a regular world, he gets the option to transfer it to a casual world. His city is then transferred in its current state to an available spot with conquest protection. Building levels, Researches, items in inventories, Heroes, Advisers, Settings, city names Event powers and other more valuable powers are transferred with the city. It is only possible to transfer one city to a Casual world.
So you received these benefits in Naucratis as a one off when you were conquered in Onchesmos. Normally you cannot transfer your extended inventory.