Complex sentence: The regiment has long being considered the only and the strongest among the other Lebanese Army regiments; however, with the introduction of the other special regiments, such as the Navy SEALs Regiment, this regiment isn't anymore considered as such.
Split into simpler sentences: The regiment has long been considered the only and the strongest among the other Lebanese Army regiments. However, with the introduction of the other special regiments, such as the Navy SEALs Regiment, this regiment is no longer considered as such.