By tradition, the president of Argentina is godparent to all seventh sons and seventh daughters born in the country; in Belgium, the seventh children are named after the reigning monarch, and that monarch also becomes their godparent.
Seven is an overloaded number in religion, folklore, and tradition: seven days in a week, seven colours in a rainbow, seven “planets” in the sky (before we had telescopes), seven deadly sins, seven circuits around the Kaaba, Seven Sleepers, seven chakras, Seven Sages, the seven branches of the Menorah, the Seven Wonders, the Seven Sisters, and the Seven Seas.
One tradition popular in pre-modern Europe imparts special powers or importance to the seventh child born to a family, especially when the only have siblings of the same gender: the last of seven sons, or the last of seven daughters. And if that seventh child grows up to have seven children of their own… well, the “seventh son of a seventh son” is bound to be a wizard, a witch, a werewolf, a vampire, or a prophet.
A hundred and fourteen years ago in Argentina, two German-Russian migrants had a seventh son. They asked José Figueroa Alcorta, then the President of Argentina, to become godparent to their child. This was in keeping with a Russian tradition, apparently, but the president took it and really ran with it. From that time on, the parents of any seventh son or seventh daughter could ask the president to become the child’s godparent. Juan Perón was godfather to 1,982 little Argentines. This was an informal honour until 1974, when this responsibility was enshrined in official legislation.
Back in Europe, the reigning king and queen of the Belgians are godparents to all seventh children born in the country. By tradition, the children are named after the monarchs and the monarchs send them gifts; in one news report from 2017, the gift was a silver dish.