On my first visit to Ireland, nearly 40 years ago, my future father-in-law drove me over to see Tudenham Park, a once-majestic Palladian mansion overlooking Lough Ennell in the Irish midlands. It was a shell. Derelict and roofless, its desolate beauty disturbed me then, as it still does today.

Nearly 300 Irish country houses were deliberately destroyed between 1920 and 1923, burned during the War of Independence and the vicious civil war that followed. The new nation lost the flower of its domestic architecture: Mitchelstown Castle, Ireland’s largest Gothic Revival castle; Summerhill House in Co Meath, one of the grandest of all Palladian mansions; and Moydrum Castle in neighbouring Westmeath, a riot of turrets and battlemented towers.

Sometimes their owners met similarly brutal fates. Families were ordered out in their night clothes and left to walk to their nearest neighbour. Servants (especially Protestants) were beaten savagely. On the night when Kilmorna House in Co Kerry was burned, its owner, Sir Arthur Vicars, was stood against one of his own trees and shot. More often, though, the IRA men who came with sledgehammers and petrol treated the occupants with quaintly old-fashioned courtesy, apologising for the inconvenience and helping to gather their belongings – before ushering them out and burning down their ancestral seats.

Sometimes the paintings were rescued, too, or had already been spirited away to England (although that didn’t stop one or two owners from claiming on the insurance). But overall, the losses were terrible: portraits by Gainsborough and Reynolds, collections of silver, priceless archives dating back centuries – all were burned, while their owners stood in the cold night and watched.

Historians have offered various reasons for what can seem, at a century’s safe distance, nothing but wanton vandalism. They argue that the burning of so many country houses was motivated by a desire to bring down symbols of colonial oppression; or by a need to destroy potential enemy bases; or by the settling of old scores. The houses of prominent and not-so-prominent loyalists were apparently burned as reprisals for Black and Tan atrocities, while after the signing of the Anglo-Irish Treaty in 1921, the homes of Irish senators were burned as reprisals for the Free State’s execution of Anti-Treatyites.