M told me today, when I took her this bouquet of muguet (moo-zhay--lily of the valley) that it all started in the USA with a May 1st (1886) strike for the eight-hour day. A few years later, the Socialist International designated May 1st as a special day for demonstrations.
In 1941 the French Vichy government made May 1 a day on which workers could stay home and still be paid. The French created Mother's day at the same time, to celebrate, peut-être, those who stay home and are not paid.
In the US, the first Labor Day was celebrated in 1882 on September 5, and it has remained in September ever since. The British have their Labor Day not on May 1, but the first Monday in May.
In France, May 1 is also La Fête du Muguet and a bouquet of lily-of-the-valley is given to friends and family in celebration of Spring and for good luck. Consider this virtual bouquet of muguet my Spring wish for good luck to all of you.