Most of Scotland's modern holidays evolved from the pre-Christian festivals of the ancient Celts and Gaels. Being an agrarian society, the early inhabitants of Scotland paid careful attention to the lunar cycle and the changing of the seasons, upon which their harvest and livelihood depended and around which their festivals developed. Samhain (1 November) marked the final harvest and the start of winter; Imbolic (1 February) heralded the first stirrings of spring; Beltane (1 May) ushered in the pastoral summer seasons when livestock herds were driven out to pasture; and Lughnasadh (1 August) celebrated the first cuts of the harvest.
As the British Isles converted to Christianity, the religious connotations of these pagan festivals were either gradually replaced with Christian overtones or evolved into secular holidays. Samhain and Imbolic, for instance, developed into All Souls' Day and Candlemas, respectively, while Lughnasadh lost its religious character altogether and was replaced by the term day, Lammas. Scottish term days divided the legal year and marked the time when rent and interest was due on loans, ministers' stipends were due, servants were hired and paid, and contracts and leases would begin or end. The other term days were Candlemas, Whitsun (the Pentecost celebration), and Martinmas, the feast day of St. Martin of Tours. (The first Mondays of May and August are bank holidays today.)
Today, Scotland's most popular secular celebrations are St. Andrew's Day, New Year's, and Robert Burns Day.