After a successful crusade in 1443–44, which penetrated all the way to Sofia and led to the restoration of the Serbian Despotate under the terms of the Szeged peace treaty, Novo Brdo was returned without a fight to Despot Đurađ Branković. Under Đurađ's vassal obligations towards the Ottoman sultan, a detachment of cavalry and a company of tunnel diggers from Novo Brdo were sent to Mehmet II (1451–1481) to aid in his attack on Constantinople, which ended on 29 May 1453 with the city's fall. According to the account of Bertrandon de la Broquière written in 1433, Đurađ was receiving 200,000 ducats out of Novo Brdo annually, while Novo Brdo mines were the most prosperous in the whole Balkan peninsula. At the time, annual income from the town was around 120,000 ducats. In 1454 the great voivode of Novo Brdo was Alessio Spani, a son of Peter Spani of the noble Albanian Spani family of Greek origin. Alessio's father Petar was also voivode of Novo Brdo under Stefan Lazarević.