|St Martinus Eve in Sweden is the evening before the Mårten Day November 11|
That is November 10. Traditionally in Scania in the southmost part of Sweden this day they eat roast goose and black soup.
Celebration of the day of St Martinus is going back to the 12th Century in Europe. This celebration is at the same time as the autumn slaughter of geese. The custom came to Scania in Sweden in the 16th century.
November 11 in Europe is the celebration of St. Martin of Tours (ca 316–397). He was a Franconian bishop and was declared a Saint. A well known story is the legend about sharing his mantle with a beggar.
This page in Swedish