For a long time, this colour did not even have a name. It used to be called “incarnate”, because it represented the colour of the flesh, the colour of the skin.
It was just a faded red. Red was the colour of power and strength: from the Middle Ages to the Renaissance, pink was in fact a manly colour! (Remember the portrait of Henri IV dressed all in pink).
It was not until the 14th century that dyers were able to create a pretty pink from Brazilian wood. But as this exotic essence was expensive, only the most powerful people could afford to wear pink.
It was not until the 18th century that pink became more democratic. According to the legend, it is to Madame de Pompadour that it owes the rise of its popularity, and its success among women. It also acquired at that time its current symbolism: romanticism, femininity and softness for the positive side, and mawkishness and futility for its less rewarding side.
On the other hand, the fashion of “pink for girls, blue for boys” is quite recent and dates only from the middle of the 20th century, and even then, in the West. Before, it was the opposite: blue, calm and soothing, was recommended for girls, while pink, more decisive, stronger, was better suited to boys’ characters.