Niobe turned into a marble due to Leto

The tale of Niobe states that Leto and Niobe quarreled and had a bad relationship because of how many kids each of them had. Niobe frequently boasted that she had more children than Leto, who was also made to travel the world, although being less fortunate. All of this came to an end when the goddess, once, overpowered by fury, heard the poisoned words of Niobe. Leto flew to Cynthus' highest point and provoked Apollo and Artemis into murdering all of her offspring. As they quietly approached them, Artemis slaughtered the daughters while Apollo killed the sons. Everything took place in seconds.

Leto's followers were being driven away from Niobe's altars because Niobe was boasting about how blessed she was and how the goddess had been reduced to having no offspring at all. Niobe, however, was ultimately the one who was childless and hence was silent, unmoving, and stone-like. A similar tale claims that Niobe, in her desperation, traveled to Mount Sipylus, where she wept until she turned to stone. After that, her husband Amphion attempted to destroy the temple of Apollo in retaliation but was murdered by the god's arrows and was sentenced to spend eternity in Hades as a result of being among those who made fun of Leto and her kids.

After this tragedy, everyone feared calling on Leto's wrath and increased their devotion to the goddess and her offspring.