Numerology describes the deep relationships between the physical world around us, events and interactions among agents in that physical world, and special cosmic numbers. These connections have been often observed throughout history, and most civilizations and religions have always had some aspect of the study within. The Greeks had many philosophies around the meaning behind numbers and math, but the more formal discipline of what we know today as numerology did not originate until much later. In fact, the term “Numerology” was not used until 1907, and is only recently gaining popularity among those that seek deeper meaning in life.
Much more information about the history of numerology can be found here on the official Wikipedia page.