The Feast of the Exaltation of the Holy Cross has its origins in the traditions of Constantinople, where the Precious Wood of the Cross was carried in procession throughout the city during the month of August to sanctify it and protect against illnesses.
On July 31, the Cross was taken from the imperial treasury and placed on the Holy Table of Hagia Sophia. From August 1 until the Dormition of the Theotokos, there were processions throughout the city, allowing the people to venerate the Cross.
This feast was established in commemoration of victories over the Bulgars and Saracens, where crosses carried by the armies were believed to have brought heavenly assistance. The true Honorable Cross, kept in the imperial church, was used in these processions for the consecration of the city.
With the prevalence of diseases in August, the tradition of carrying the Cross for sanctification and protection from illnesses was upheld in Constantinople. The Cross was paraded through the streets for veneration before being returned to the imperial church on August 14.