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I searched on the subscription site Roots Ireland and did not find a baptismal record for Julia. I did find a record for a Jeremiah Breslan in 1835 which may be a brother. I also noted that the Milford/Freemount RC parish has a gap in their baptismal records from April 1840 to July 1843 https://registers.nli.ie/parishes/0052 I don't know how old Julia was when married but if she was in her late teens then possibly the record is not available.
Name:Jeremiah BreslanDate of Birth:
Date of Baptism:02-Oct-1835Address:
Father:Thomas BreslanMother:Elizabeth CarrolOccupation:
Sponsor 1 /
Informant 1:Timothy Sullivan Sponsor 2 /
Informant 2:Mary Breslan