1968: Scudetto arithmetically won in March, a unique event from 1929/30 to date
In 1968, four matches ahead of the end of the championship, AC Milan won the 9th Scudetto in their history, beating Brescia 1-0 at home, with a goal in the second half by Gianni Rivera, bringing to +9 the advantage over the second placed team, Varese and Inter, paired together. At the time the victory still gave two points. This is - still today - the only Serie A title to be won arithmetically in March.
Source: legaseriea.it