Mary Neilson was a convert to Catholicism who, after a distinguished career in medical social work, emerged as one of the most significant figures in the worldwide Catholic traditionalist movement.

Mary was born in 1912, the child of two established families. Her father was an Army officer and she had a comfortable and secure Presbyterian upbringing in Edinburgh and completed her school education at St Leonard's School, St Andrews. When she was 15, she determined to join the Roman Catholic Church; but in deference to the wishes of her family, she took the matter no further at that time. On leaving school, she studied social work at Edinburgh University after which she went to London to embark on a career in medical social work. In 1938 she was received into the Catholic Church. That decision was to cost her with numerous family estrangements.

During the war she served as a civilian welfare officer in the war office. From 1945 to 1947, she served in India as a welfare officer for the Forces Help Society before moving to Germany as a relief officer and youth welfare officer, assisting refugees and displaced persons. These experiences confirmed her in her international range of vision. She continued her work for refugees in London until 1951 when she went on atour of work and study in Canada and the United States.

She returned to the United Kingdom in 1954 and spent the next six years in social work in the north-east of England. In 1960 she returned to Edinburgh as a research worker for the Chest and Heart Association. This work led to the publication in 1965 of a significant study, undertaken with Dr Eileen Crofton, of the social effects of chronic bronchitis. From then until her old age, she continued to travel widely.

In 1965, when most Catholics were still unaware of the implications of the liturgical changes proposed by the Second Vatican Council, Mary became a founder of Una Voce Scotland, a society dedicated to the preservation of the Latin liturgy. At that stage the only issue was the survival of the universal language of the Church. For Mary, worse was to come. In 1969, the Catholic Church introduced the new rite of Mass. Mary was dismayed by the loss of a rite that had

united Catholics.

In Scotland, the main problem for traditionalists was that the old Mass, though freely available elsewhere, was permitted in Scotland only

on restrictive conditions. In Mary's view, these restrictions played into the hands of the schismatic Lefebvre movement which had set up churches in both Edinburgh and Glasgow. Over the years she engaged in a fruitless correspondence with the Scottish hierarchy in an attempt to have the restrictions lifted. It was unfortunate that she died only days before the first public celebration of the traditional Mass by a Scottish bishop since the liturgical changes of 1969.

Until her final illness, she maintained the private celebration of the old Mass in the oratory of her house.

When she was not engaged in her extensive daily correspondence, she spent most of her time in prayer and spiritual reading. She took no satisfaction in the decline in the Catholic Church in the post-conciliar years.

Her contribution to Catholic tradition extended far beyond her native land.

Mary has bequeathed the bulk of her estate to the Society of St Peter, a traditionalist congregation within the Church.

Mary Georgina Cummings Neilson, social worker; born December 24, 1912, died September 12, 2002.