There were apparently already people with COVID symptoms in Italy back in December 2019. That said, China was already aware of the virus in late 2019. It's all well known.
>>ekianj+(OP)
Well, that's what I mean. Nobody knew COVID was circulating in Italy at the time either. It's easy to miss a new respiratory virus. For it to originate one place and by chance end up exploding in a different metropolitan area doesn't seem unlikely at all.
>>roywig+u1
In fact, simply from a modelling perspective, this is very likely scenario.
If you take an unknown diseases with an R of 2-3, what you will see is a number of smaller clusters, some dying off, before you get the one cluster that becomes the pandemic.