Not alone, which is her doing as well. Star Swirl was more or less setting her up as an absolute monarch, but from what we’ve seen Equestria is more or less run as a pretty functional and effective democracy that she arbitrates and oversees.
For all the tyrant Celestia memes, she seems to have built up a pretty impressive amount of subtle power, hidden behind a very extravagant public persona that the population are still eating up after a thousand years.
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