Florists launched a major promotional effort in 1925. This included the publication of a book of articles written by famous intellectuals, radio broadcasts, newspapers ads, and the collaboration of priests and teachers who wanted to promote the celebration for their own reasons. In 1931 the second Sunday of May was adopted as the official celebration date. In the mid-1930s the slogan "Moederdag – Bloemendag" (Mother's Day – Flowers' Day) was coined, and the phrase was popular for many years. In the 1930s and 1940s "Mother's Day cakes" were given as gifts in hospitals and to the Dutch Queen, who is known as the "mother of the country". Other trade groups tried to cash in on the holiday and to give new meaning to the holiday in order to promote their own wares as gifts.