The article treats the dating criteria of the hieroglyphic inscription SÜDBURG. Since its publication by D. Hawkins in 1995 the inscription is firmly believed to belong to the reign of the king Suppiluliuma II. However, a thorough look at the publication reveals that the grounds this attribution is based on are rather weak. Firstly, the identification of TONITRUS.URBS.REGIO attested in the inscription with Tarhuntassa, which would define the first quarter of the 13th century BC as terminus post quem, does not prove to be as unequivocal as believed before. Secondly, in the light of new discoveries in Hattusa made in the last 15 years the archaeological dating of the complex where the inscription was found («Southern Citadel») to the reign of Tudhaliya IV, proposed a priori by P. Neve, turns out to be highly doubtful as well. Last, the alleged absence of substantial hieroglyphic inscriptions before the 2nd half of the 13th century BC cannot be accepted as an argument against an early dating of SÜDBURG at all, since the hieroglyphic script had been invented long before. On the other hand, at first glance one can notice a sharp discrepancy between the appearance of the hieroglyphic signs of SÜDBURG and those of the late Empire inscriptions, such as YALBURT or EMİRGAZİ. A closer glance reveals that the inscription is distinctive at all levels of text organization: by its sign forms, by the presence of a large number of unattested or rare signs and especially by the mode of purely ideographic writings, in stark contrast to the high percentage of late Empire phonetic writings. But the most decisive argument for the early dating of the inscription is the writing of the name and titles of Suppiluliuma. Not only do the forms of the signs PURUS and MI prove to correspond to the writing of the name of Suppiluliuma I as attested on his seal impressions, but also the mode of giving only two titles (MAGNUS.REX HEROS) is fully concordant with the attribution of the inscription to this king: as it is clearly demonstrated by NİŞANTAŞ and by some other texts, these titles of Suppiluliuma II are constantly supplemented with the title LABARNA+la and his genealogy. In sum, the graphic peculiarities of the inscription taken unbiasedly unequivocally speak for the attribution of the text to the reign of Suppiluliuma I.