The genesis, concept and  structure of Ulysses are unimaginable without Trieste.
For Ulysses, while ostensibly about Dublin, is in reality a tale of  two cities in which the second city, Trieste,  is mentioned only once explicitly, in the ‘Eumeus’ episode. In Ulysses there is a continuous and complex doubling of persona, settings and events, in which elements, persons and experiences which Joyce encountered in Trieste are overlaid upon or appear as counterpoint to his meticulous and seemingly direct re-creation of Dublin. Some of these elements are quite evident, from the protagonist, Leopold Bloom, a converted diaspora Jew of Central European origins whose name is most likely the composite of two Triestine business partners, Leopoldo Popper  and Adolf Blum, to elements which Joyce first encountered or came to know more fully in Trieste: psychoanalysis, Futurism, opera, a very particular expression of Judaism,  Orientalism,  and so forth.

Others are very specific, obscure:  the name of a soap or a hat, specific words and allusions, while still others are very subtle and circumstantial and more difficult to demonstrate: the distinctly Triestine elements of contamination, corruption (especially linguistic) and hybridisation, and perhaps most importantly, the issues of identity, belief and history.

Ulysses  is the epic of Dublin as seen through the eyes of someone who had lived for 10 years in Trieste and its dynamic and structure owe much to the alternation and juxtaposition of the pre- and post-Triestine Joyce, of Stephen Dedalus and Leopold Bloom who view the world from their radically different perspectives, and in which the events of Joyce’s life are contextualised in Dublin, but often  receive their meaning and resonance thanks to Trieste.