Hera
When Hera found out that Leto was pregnant with twins by Zeus she was angry. She banished Leto from Olympus, she also banned her from giving birth on any mainland or island that was known. Leto found a floating island, called Delos. It was neither a mainland or a real island, so Leto was allowed to give birth there. Artemis was born first, who then helped Leto to give birth to Apollo. After Artemis and Apollo was born, Hera was furious. So she sent the snake-monster, Python to hunt Leto and her twins. When Apollo reached to his adulthood, he slayed Python in Delphi and decreed that the humans will built a temple there in honour of his victory against Python. Few years later, Hera sent a giant named Tityos to rape Leto, but he was killed by Apollo and Artemis. Delos was later held down with four pillars so that it would not float around anymore. It is said to be surrounded by swans and later became a sacred place to Apollo.