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I searched on Roots Ireland and did not see a baptismal record for a Stephen Saunders/Sanders. The Strokestown records start in 1830 but the Ogulla records do not start until 1865. I did find one Mary Coyne record in Strokestown in 1862. (see below). Possibly one or both were baptized in Ogulla prior to 1865.
I did find this family in the 1901 and 1911 censuses. Is this the family you are looking for? They married February 11, 1897. The names of their fathers were John Saunders and Michael Coyne. Go to the third link below to see the civil marriage record. You may have to sign in to see the record.
Name:Mary CoyneDate of Birth:06-Apr-1862
Date of Baptism:1-Jan-0Address:NgParish/District:STROKESTOWNGender:FemaleCountyCo. Roscommon
Father:Michael CoyneMother:Anne KeefeOccupation:
Sponsor 1 /
Informant 1:Edward Keefe Sponsor 2 /
Informant 2:Sarah McDermott