The Holy Cloth was the first nappy that was wrapped on baby Jesus at the moment of birth. According to legend, the relic came to the Seu Vella by the hand of Arnau Solsona, a merchant of Lleida who was jailed in Majorca with his wife, Elisenda, and their daughter Guillamona during a raid that the king of Tunisia made on the island. Once in Tunisia, Guillamona was married to the son of the king, which allowed her to discover the treasures of the palace, among which she found the Holy Cloth. Secretly, she took it and gave it to her mother, who once back in Lleida, and shortly before her death, confessed possession of such a precious relic to her husband.

Arnau Solsona donated the Holy Cloth to the cathedral in 1297. The relic, worshipped and revered since then, having been saved from all the misfortunes it lived, was lost forever during the Civil War. However, a few threads of the Holy Cloth are preserved in Barcelona and others in the Escalona del Prado (Segovia).