[Jim McDougall]

That really does seem like an outstanding blade, and most unusually so for these type of Persian trade blades. I personally know little of metallurgy in these wootz patterns, but the examples of these 'Assad Adullah' blades I have seen are usually with channels or fullers, wider blade and typically of lesser quality wootz patterns.

According to the brilliant article by Oliver Pinchot, "The Persian Shamshir and the Signature of Assad Allah", ("Arms Collecting", The Journal of the Canadian Arms Collecting Society, Vol. 40, #4, Feb. 2002), these kinds of blades bearing a cartouche and a pictogram representing 'Assad Allah' (=Lion of God), began appearing late 18th and into 19th century.

This represented a marketing shift for Persian blades into varied markets, particularly to those in Arabia, where they were highly favored over others.
It is noted that among possible reasons for the continued use of the name of this famed sword smith of centuries earlier, one potentially feasible is a tradition recognizing Assad Allah and his contributions to Persian sword guild.
An exemption from taxes for 300 years said to have been granted by Shah Abbas (1567-1628) for the swordsmiths guild, may have prompted this commemorative use of the Assad Allah name.
Aside from this tradition, the imbuement of quality certainly was present as well.

It is noted also that the Kirk Narduban term was a transliteration from Turkish 'kirk' (= forty) and 'merdeven' (=steps/stairs) , while more commonly termed ' The Forty Steps of Mohammed'.

A very, very nice example of sayf Badawi!