Although the stories about Hurrem's role in executions of Ibrahim, Mustafa, and Kara Ahmed are very popular, actually none of them are based on first-hand sources. All other depictions of Hurrem, starting with comments by sixteenth and seventeenth-century Ottoman historians as well as by European diplomats, observers, and travellers, are highly derivative and speculative in nature. Because none of these people – neither Ottomans nor foreign visitors – were permitted into the inner circle of the imperial harem, which was surrounded by multiple walls, they largely relied on the testimony of the servants or courtiers or on the popular gossip circulating around Istanbul. Even the reports of the Venetian ambassadors ("baili") at Suleiman's court, the most extensive and objective first-hand Western source on Hurrem to date, were often filled with the authors’ own interpretations of the harem rumours. Most other sixteenth-century Western sources on Hurrem, which are considered highly authoritative today — such as "Turcicae epistolae" (English: "The Turkish Letters") of Ogier de Busbecq, the Emissary of the Holy Roman Emperor Ferdinand I at the Porte between 1554 and 1562; the account of the murder of Şehzade Mustafa by Nicholas de Moffan; the historical chronicles on Turkey by Paolo Giovio; and the travel narrative by Luidgi Bassano — derived from hearsay.