The month of October is named after the Latin word for eight – octo – because it was originally the eighth month in a ten-month Roman calendar.
October became the tenth month when the Julian calendar was introduced in 45BC. At that time the months of January and February were added to the calendar.
In the middle of the month on 15 October, there was a Horse Ceremony dedicated to Mars in the Campus Martius, involving animal sacrifice. Mars was second in command to Jupiter in the hierarchy of the gods and he was in charge of military matters.

Other festivals in October celebrated the Penates – the household gods – as well as the Festival of the Wolves called Lupinalia (remember Romulus and Remus were suckled by a she-wolf) – as well as other ceremonies dedicated to Emperor Augustus, Jupiter Fulgar (God of Daytime Lightning), and the festival of Ieiunium Cereris, a day of fasting dedicated to the goddess Ceres which took place on 4 October.

October is an excellent time to visit Rome as it can still be very warm right up to the end of the month, with cooler nights which are still workable if you like an evening stroll.
Daytime temperatures can reach 25C (75F), so pack a pair of Roman sandals, just in case, and enjoy feasting and fasting like an Ancient Roman!

Buon viaggio!