If you wish to read chronologically, then Men of Iron is where you should start your journey through Saxon England with MJ Porter. The books weren't written chronologically, however, as I have a tendency to work backwards.

Yes, The Eagle of Mercia Chronicles and The Last King/The Ninth Century Series feature Icel, both as a young man (in The Eagle of Mercia Chronicles) and then as an older character (in The Last King books). There are also strands woven through the series, most notably, the eagle emblem for the books about Saxon Mercia.

Yes, but it's not imperative. The Custard Corpses, The Automobile Assassination, and The Secret Sauce feature the same detective but aren't connected aside from the occasional reference.

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