First Active was founded in 1861 as the Workingman’s Benefit Building Society. It was incorporated in Ireland in 1875 under the Building Societies Act, 1874. In 1960 the name of the Society was changed to First National Building Society. Over a period of years First National grew both organically, through expansion of its branch network, and by the acquisition of the business of five small building societies:

• Grafton Savings and Building Society, acquired in 1974
• The Guinness Permanent Building Society, acquired in 1984
• Ireland Benefit Building Society, acquired in 1984
• Irish Life Building Society, acquired in 1993, and
• Postal Service Permanent Building Society, acquired in 1985.

In 1994 First National acquired Mortgage Trust Limited, a UK centralised mortgage lending business. In 1995 a deposit taking subsidiary commenced business in Guernsey, Channel Islands. The Group’s UK operations were expanded in 1996 through the acquisition of The Mortgage Corporation. A retail deposit taking operation was established in England in 1996 to obtain sterling deposits to fund the Group’s growing mortgage business in the UK.

Info gleaned from Wikipedia