Charles Haughey considered giving Margaret Thatcher a gift inscribed with a St Francis of Assisi prayer she recited after taking power.
The Taoiseach discussed with the Irish Ambassador in London a "suitable inscription" to be used on a token when the two leaders met for the first time in 1980.
Mr Haughey famously opened relations by giving the then-British PM a Georgian silver teapot. As relations between the two leaders hardened over the years, officials used to joke that the rest of the tea set would be a long time coming.
State papers released under the 30-year rule showed that Mr Haughey had asked Irish diplomats for advice. One official wrote back suggesting the St Francis prayer "Lord make me an instrument of your peace".