Season 14

14×01: Death in the Slow Lane

In July in the 1950s: Duncan Palmer from Midsomer County wins the British Grand Prix in Silverstone. (Note: It is also possible that it was a previous Formula 1 race, but not after. Palmer died in 1962 and neither 1961 nor 1962 was the British Grand Prix held at Silverstone. Alternative years would be 1958, 1956 or between 1951 and 1954, as these were the years when both the races were held at Silverstone and Stirling Moss was active).
Deep Dive: Sports History in Midsomer, pt. 2: Other Sports

1962: Formula 1 racing driver Duncan Palmer from Midsomer County is murdered in a barn near Midsomer-in-the-marsh.

14×02: Dark Secrets

1914/1918: Frank Bingham sold cheap, inferior food to the Ministry of Defence during WW1 and did very well for himself. He set up a huge trust fund for his new fortune. A trust fund that will run out as soon as William and Mary Bingham die.

1960s: Bertie Morell founds an artist community in Midsomer Parva. Shortly afterwards he dies (“drank himself to death”).

14×05: The Sleeper Under the Hill

Sometime between the 5th and the 7th century (Anglo-Saxons): A battle between Norsemen (Vikings) and Saxons takes place at Gorse Meadow in Midsomer Mow – the Battle of Hallows Beck. The Saxons were victorious.
Deep Dive: Treasures & Raiders in Midsomer County

14×06: The Night of the Stag

Deep Dive: The Dantean Anomaly (and briefly into edict and horn dance)

669: The Pope condemns the Beltane cult, in which men fight each other with stags on their heads, and declares in an edict: “Whoever at the Calends of January [that’s January 1st] goes about in the form of a stag, that is changing himself into the form of an animal, dressing in the skin of a horned beast and putting on the head of a beast, who in such wise transform themselves into the appearances of a wild animal, penance for three years, because it’s devilish!

1370: In Midsomer Abbas, there are long frosts in the spring that stunt the year’s harvest and brought starvation to many residents. They get help from the neighbouring village “over the valley”, Midsomer Herne, who bring part of their apple harvest.

1880s: The dangerous Horn Dance (actually a fight between men wearing deer antlers) in Midsomer Abbas develops into an amusing, bloodless dance.

14×07: A Sacred Trust

Before 1930: Foundation of Midsomer Priory in Midsomer Vertue. In 1930 Mother Jerome’s great aunt was prioress.