Second attack on Constantinople
The second time, in 43 Hijri the Muslims attacked Rome under the leadership of Hadhrat Busr bin Artaah (May Allah be well pleased with him) and fought their way to Constantinople. It is written in Bidayah Wan Nihayah Vol. 8, Pg No. 27:
A critical historian of the like of Ibn Khaldun has also mentioned this incident. It is written in Tarikh Ibn Khaldun, Vol. 3, Pg No. 9:
Translation: Then Hadhrat Busr bin Artaah (May Allah be well pleased with him) entered the country of Rome in 43 Hijri. He kept moving forward till he reached Constantinople.