Unfortunately, the early history of pasta is mysterious. There are some possible candidates for pasta in ancient Greco-Roman cooking (itrion/itrium and laganon/laganum), but the general consensus is that they were not pasta. How do we define pasta? Serventi and Sabban (2002) define it as a food made from unleavened kneaded dough that is cooked by boiling.

The earliest pasta/noodles appear to be Chinese, with an archaeological find of millet noodles aproximately 4,000 years old, textual references to noodles during the Han Dynasty, and stuffed dumplings, with as much right to be called "pasta" as ravioli, were already being made and enjoyed in the 3rd century.

In the West, a better pasta candidate than the earlier Greco-Roman mystery foods appears in Palestine in late antiquity (3rd to 5th centuries AD), called itrium, but unlike earlier itria, is described as a dough that is cooked by boiling. Is this a descendant of older Mediterranean itria etc.? Is it something new? Transmitted from China? We don't know - we don't know enough about this Palestinian itrium, and even less about earlier itria. We don't even know for sure that we should call it "pasta".

Isidore of Seville, in the early 7th century, described a laganum

a broad, flat bread, which [is cooked] first in water and then fried in oil.

as quoted by Serventi and Sabban (2002). As a dough product that is cooked by boiling, this is a good candidate for pasta. The description isn't detailed enough to be certain that it was really pasta.

Somewhat later, in the 9th century, we find itriyya in the Syria-Palestine region: spaghetti or vermicelli made from semolina. Unambiguous pasta! This appears to have spread around the Mediterranean, likely due to the Arab conquests, and 12th century Sicily became a major pasta producer and exporter. The export sales mean that the product was dried - the ancestor of our modern dry pasta had arrived. This is long before Marco Polo, so clearly the Polo myth is just that: a myth without basis in fact.

Thus, the ancestor of modern pasta appears to be itriyya. The mystery - to which we have no good answer - is whether itriyya developed from the older itrion/itrium which it was named after, and whether those might have been pasta, or whether it was an invention of Western Asia, or whether it came from China.

Reference:

Serventi, Silvano and Sabban, Françoise (2002), Pasta: the Story of a Universal Food, Columbia University Press.