According to new research, the textiles are much younger than the apostles.
They date from the 3rd and 6th to 7th centuries respectively, according to Alessandro Vella from the museum's Department of Christian Antiquities.
On Thursday evening, the Vatican Museums presented the restored vestments and new findings from around five years of analysis.
The dalmatic and the oriental-style tunic had been locked away for centuries in the former private chapel of the popes in the Lateran Palace.
It was not until the beginning of the 20th century that Leo XIII (1878-1903) decided to release the relics.
According to researchers, the preservation in cypress caskets, barred under the altar of the chapel above the Holy Staircase, is the reason why the textiles were able to survive the many centuries.
Possible reason for the misconception
According to Vella, there is no information about the origin of the vestments in the treasure itself.
Only some writings and legends provide references to the textiles that can no longer be traced today.
In addition, the precious relics were presumably relocated within the chapel, which makes it difficult to assign literary references. There could also have been mix-ups in inventory lists.
Another possible reason for the false assumption is a special relic practice, according to Vella.
Objects that actually came into contact with saints were rare, so secondary relics were used. For example, a tunic that was worn devoutly for a few days at the tomb of St Peter could absorb the saintly virtues and in turn become a relic itself, explains the scientist.
The same could possibly apply to the dalmatic associated with St John the Evangelist.
The Vatican Museums recently completed the restoration and conservation of the centuries-old vestments.
The garments are now on display as part of the exhibition "The Vestments of St Peter and St John, two extraordinary relics of the Sancta Sanctorum" in the hall behind the Sistine Chapel.