Islamic/Eastern European Crossguard

[B.I]

hi,
i am currently looking into the origins and dating system for this specific type of quillion block.
all books tend to assume the earliest form goes to the 17thC (and of course into the 19thC), but i wonder if this assumption is becauce few (if any) earlier examples exist. i personally feel it could go a few hundred years earlier.
please note the proportions, the rounded quillion ends and the ridge before the elongated ball-ends.
these hilts were on eastern european as well as islamic swords so i was hoping i could tap into some knowledge of other cultures on this forum.
unfortunately, this is for academic use and so hard data (in known swords and iconography) are needed as apposed to speculation.
the swords in yucels book are of no use, as the hilts of this type are of a later date.
i feel the answers may lie in eastern europe, but am hoping a mamluk or ottoman reference will show itself. the proportions have to be very similar, or at least the quillion ends (and not the width of the block).
much appreciated, as ever.