The death has been announced of Dermot Nally - one of the country's most prominent civil servants. He was 82.
Mr Nally, who served under five Taoisigh, died suddenly in St Vincent's Hospital in Dublin this morning.
He led officials in the negotiations leading up to the 1985 Anglo Irish Agreement and was also involved in the negotiations preceding the 1993 Downing Street Declaration.
The Taoiseach said Mr Nally’s death will be noted with regret by all those he worked with over the years.
Mr Cowen said Mr Nally would be particularly remembered for his contribution in relation to Northern Ireland.
He offered his sympathy and that of the Government to Mr Nally’s family.
Mr Nally is survived by his wife, Joan, brother Fergal, sister Sheila, son Brian and daughters Ailbhe, Maura, Sheila and Catriona.