It was not explained yet. But the current guess is Lily did that
It's hinted that she and Lyrica are first borns, he mentions it as the third group of people that can use magic. It was when they were in the garden together before the fire.
Right, from that it was confirmed Lily is a mage and one that could be extremely powerful. But I wasn't sure about the mother, though Lily had to have inherited it from somewhere so it makes sense the mother has some sort of ability she wasn't aware of.
The focus has been on Lily being a mage though so that's why I figured she must have been the one to turn back time
What gives it away is that they mention time travel as part of their abilities and if you go to the beginning I believe there was clocks when her mom was waking up from her past life
How Lily's mom went back to the past? Maybe I just can't recall since it's been a while since I read S1 buuut
What if Lily is the one who turned the clock? She is a mage. The only mage. What if after her and her mothers executions she, a pure kid who loves her mother and wants to protect her till the end, wished for the time to go back so her mom would be ok. So the one whose clock rewound is the mothers and its why Lily doesn't have any past memories but the mother does. Just a thought esp with how the emperor is like, yep she's gifted.