This paper aims at investigating the influence of the civil war of 69 AD over G. R. R. Martin’s series A Song of Ice and Fire, drawing special attention to the legitimacy of the pretenders to the iron throne. Although it is a well-known fact that G. R. R. Martin’s principal inspiration is the War of the Roses, I argue here that the similarities between the novels and the first civil war of the Imperial era, as depicted in our main source, Tacitus’ Histories, are too obvious to ignore, as hinted by a recent study (Haimson Lushkov 2017, epilogue). The first step is to highlight structural similarities between Martin’s political plot and the years 68-70 AD, which lie mainly in the simultaneous claims to power of multiple pretenders from distant areas of the Empire and in their rivalling legitimacy. The distinctive characteristics of this legitimacy (decisive acceptance by local armies, significance of controlling the capital city, etc.) brings A Song of Ice and Fire closer to the Roman period than to any other. This emphasizes how Martin, far from artificially matching the moral personalities of the historical and the fictional characters, has drawn on Tacitus’ political polarisation of space between the North (Robb/Vitellius), the capital (King’s Landing’s Robert-Jeoffrey Baratheon/Rome’s Nero-Galba-Otho), and the East (Daenerys/Vespasian). Analysing also the noticeable reshaping process of this historical material by Martin (e.g. Nero’s retractatio in Joffrey and the chronological reversal with Robert/Galba), we shall see how the combination between narrative devices inspired from the annalistic style of Tacitus’ works (e.g. the alternative focus on distinct spaces) and features peculiar to the modern novel (e.g. the internal focalisation) enables the author to represent and invstigate political chaos.