Sarmatian origins of the spatha?

[Conal]

As for the spatha, you have a point. Perhaps a good one. I had always assumed the spatha would have originated with the Celts, yet the Celts were in Roman service for over a half century before the spatha shows up. Why wasn't the long sword adopted in the latter part of the 1st century BC? Also the Celtic "longsword" was about 20cm shorter than the Alanic one, somewhere between a gladius and the fully-developed spatha. This whole thing intriques me, as mentioned in an earlier post.

I had assumed that a fully developed spatha was somewhat 75-80cm in blade length, similar to Celtic/Germanic ones and not 100cm as for a two handed sarmation blade.

at AD40-60 to maybe AD100 the Roman gladius reached it's shortest at 45-55cm. Their cavalry must have had something longer than this? Ceasar used Gallic & German cavalry 100 years earlier when a Celtic sword was at 75-80cm on average. They adopted Gallic helmets from this period, the Gallic saddle and not the sword?