İstanbul Two separate rectangular blocks with Hieroglyphic Luwian inscriptions are unprovenanced, but both are likely to have originated from Neo-Hittite kingdom of Tabal in central Anatolia and date to around the 9th to 8th century BCE. İstanbul 1 has been known since the early years of 20th century and came into Istanbul Museum from an antiquities dealer. It is the bottom part of a rectangular stele with a line of inscription surrounding all 4 sides, and measures about 39 cm in width, 25 cm in thickness, and the preserved section is 21 cm in height. İstanbul 2 is in the private Haluk Perk collection and has more damage. It is inscribed on three sides but unclear whether the damaged fourth side also had an inscription or not. It is about 37 cm in width, 22 cm in thickness and the preserved section is 42 cm in height. Although in similar size, the fragments must belong to different monuments. Click on the pictures for larger images.
İSTANBUL 1	İSTANBUL 2

Literature:
Hawkins, J. D. Corpus of Hieroglyphic Luwian Inscriptions, Vol 1, Berlin, 2000: 561–62 and plt. 319. (İSTANBUL 1)
Taş, İ. and M. Weeden. "ISTANBUL 2: a hieroglyphic fragment from Tabal in the Haluk Perk Collection," Anatolian Studies 61, 2011: 55–60.

Image sources:
J. David Hawkins, 2000 (photo: I. J. Gelb).
İlknur Taş, 2011.