I'm sorry this post is late. Our cat Hugo is very ill and it's been a long and sad few days. Some things fall by the wayside a bit, but I'm trying to keep up. A repost then, in honor of Hugo.

As you are probably all well aware, the ancient Egyptians were big fans of cats, and one of their main Goddesses, Bastet, Goddess of protection and motherhood, carried the head of one. Alexandria had a temple to Bastet, for example, so the ancient Hellenes would have come in contact with Her. Most likely not everyone, but at least a few of the ancient Hellenes would have equated Bastet with Artemis--especially in Late Antiquity. Bast was a lioness goddess of the sun throughout most of Ancient Egyptian history, but later she was changed into the cat goddess Bastet. She also was changed to a Goddess of the moon by Hellenes occupying Ancient Egypt toward the end of its civilization. In Hellenic mythology, Bast also is known as Ailuros. Hyginus, for example, in his 2nd century AD 'Astronomica' writes:

"Egyptian priests and some poets say that once when many gods had assembled in Egypt, suddenly Typhon, an exceedingly fierce monster and deadly enemy of the gods, came to that place. Terrified by him, they changed their shapes into other forms: Mercurius [Hermes] became an ibis [the god Thoth], Apollo [Apollon], the bird that is called Thracian [the god Horus], Diana [Artemis], a cat [the goddess Bastet]. For this reason they say the Egyptians do not permit these creatures to be injured, because they are called representations of gods." [2.28]

You can read more about this bit of mythology here.

Returning to ancient Hellas--and not so much the Roman era--the question of the cat as a pet in ancient Hellas is rather vexing. Modern Athens is home to countless feral cats, however, the status of the cat in ancient Hellas is unclear, as images of cats are fairly rare. This is obviously a sign that even if there is a God or Goddess of cats in the ancient Hellenic pantheon cats are most likely a side-line.

Cats were probably kept by Greek households as liminal animals--animals who were free to come and go as they pleased, roaming houses and streets alike. This may account for the fact that few cat bones have been found in domestic situations. Historically, the main reason to keep cats is to get rid of mice, only in ancient Hellas the job of 'mouser' seems to have been handled by weasels and ferrets, many of which were also considered liminal pets. Yet some clear representations of cats do exist, primarily on funeral stele. These show caps on leashes, or being shown off as prized possessions, so we do know that some cats were updated to the status of 'pet'. The comic playwright Aristophanes liked to include cats in his productions and often used the phrase 'the cat did it' for comic effect, as cats were blamed for things breaking in the household.

So no, there isn't a God or Goddess of cats, but there is a Goddess associated with cats: Hekate. There is one single piece of mythology I have to base this on: the myth of Galinthias, the nurse of Alkmene, transformed by the angry Eileithyia, but received by Hekate as her animal. Again, I have only late sources, second century AD again, although this time recorded by Antoninus Liberalis in his 'Metamorphoses':

"At Thebes Proitos had a daughter Galinthias. This maiden was playmate and companion of Alkmene, daughter of Elektryon. As the birth throes for Herakles were pressing on Alkmene, the Moirai (Fates) and Eileithyia (Birth-Goddess), as a favour to Hera, kept Alkmene in continuous birth pangs. They remained seated, each keeping their arms crossed. Galinthias, fearing that the pains of her labour would drive Alkmene mad, ran to the Moirai and Eleithyia and announced that by desire of Zeus a boy had been born to Alkmene and that their prerogatives had been abolished.

At all this, consternation of course overcame the Moirai and they immediately let go their arms. Alkmene’s pangs ceased at once and Herakles was born. The Moirai were aggrieved at this and took away the womanly parts of Galinthias since, being but a mortal, she had deceived the gods. They turned her into a deceitful weasel (or polecat), making her live in crannies and gave her a grotesque way of mating. She is mounted through the ears and gives birth by bringing forth her young through the throat. Hekate felt sorry for this transformation of her appearance and appointed her a sacred servant of herself." [29]

And Dionysos, He is God of wild, predatory, felines--of those felines who pose a wild threat, who can rip flesh and inspire fear. I doubt He looks out for the smaller felines as well, although of course you could ask if you have a feline companion you are worried about. Your best bet, though, would seem Hekate to me, as She has taken mercy on felines before.