Mobile Mass Altar

"This altar I found in a hayloft in my grandmothers farmyard, it was hidden in a pile of old hay hence the poor condition it is in. At the time I unearthed it my uncle told me that my grandfather kept it hidden during the rising and it would be used in the hayloft or at a mass rock to celebrate a mass for the volunteers and those on the run from the British Army and Royal Irish constabulary. In the middle of the altar you can see the tabernacle which inside painted and sign of cross for the chalice to be held. Inside I found a page which I have attached in photos. Unfortunately, all members of my family who might have had knowledge about the altar are deceased and I would love to hear from anyone who might know of the altar being used or the significance of the page attached."