Many Irishmen, like my 3x great-grandfather General Patrick Edward Connor, were firm in stating that they were born on St. Patrick’s Day.
There is more than enough information and documentation of Gen. Connor’s military career and adult life, but scant details are available about his early life in Ireland. Many immigrants anglicized or altered states to assimilate into their adopted homeland, thus Patrick Edward O’Connor dropped the prefix in his surname and became Connor. Brigham D. Madsen, General Connor’s biographer and author of Glory Hunter, had attempted to clarify and bring to light the true birthdate of General Connor. In the footnotes of Chapter 1 in the biography, he notes that in 1988, he had written to the Diocesan Secretary of the Bishop’s House, Killarney and asked for a search of the Catholic Parish Registers. While possible matches were located, nothing was conclusive as Patrick Connor never gave the name of his parents. 
An act of Congress approved 29 January 1887 (24 Stat. 371), provided pensions for veterans of the Mexican-American War who has served sixty days, or their widows who had no remarried. On my trip to Washington back in 2009, I had requested Gen. Connor’s pension file at the National Archives. It was a massive file and showed he received pensions for both the Civil War and Mexican War. On his declaration for survivor of pension, he states his birthdate as 17 March 1820.  Many other secondary sources including newspaper articles, early biographical accounts, and more, would take the St. Patrick’s birthday as fact.
General Patrick Edward Connor’s Declaration for Survivor of Pension. Photo taken by author at the National Archives, Washington, D.C. (2009)
As a staunch Irish catholic, General Connor would have considered St. Patrick, who brought Christianity to Ireland in the 5th century, a revered figure at the very least. Based on the fact they also shared the same name, there’s no reason why he wouldn’t give his birthdate at St. Patrick’s Day. While part of this stemmed from pride and affinity for heritage, many Irish immigrants came from very poor backgrounds and simply didn’t know their birthday, so the holiday was used quite often as the date of birth.
For genealogists seeking the truth, this can be frustrating. With the release of millions of Irish Catholic church records to online databases, including Ancestry.com and FindMyPast, many researchers can dig into these records to find the correct or more accurate genealogical information of their ancestors.
 Madsen’s analysis and research on General Connor’s birthdate can be found in footnotes 3-8 of Chapter 1. See Brigham D. Madsen, Glory Hunter: A Biography of Patrick Edward Connor (Salt Lake City, UT: University of Utah Press, 1990), 4.
 National Archives and Records Administration. Genealogical Research in the National Archives (Washington, D.C.: National Archives Trust Fund, 1985), 127.
 Patrick Edward Conner (Captain, Texas Vol., Mexican-American War), pension application no. O 21603, Case Files of Approved Pension Applications…, 1861-1934; Civil War and Later Pension Files, Record Group 15: Records of the Department of Veteran Affairs; National Archives, Washington D.C.
Mark Pratt. “Ancestry.com makes 10 million Catholic records from Ireland available free.” The Seattle Times, posted 11 Mar 2016. http://www.seattletimes.com/nation-world/going-green-ancestry-com-indexes-millions-of-irish-records/
Pat Richley-Erickson. “FindMyPast: 10 million Irish Catholic Parish Registers.” DearMYRTLE’s Genealogy Blog, posted 5 Feb 2016. http://blog.dearmyrtle.com/2016/02/findmypast-10-million-irish-catholic.html
Copyright (c) 2016 Jake Fletcher.
Jake Fletcher, “St. Patrick’s Day – The Birthday of General Patrick E. Connor and Many Other Irishmen.” Travelogues of a Genealogist, posted 17 Mar 2016. https://fletcherfamilytree.wordpress.com/2016/03/17/st-patricks-day-the-birthday-of-general-patrick-e-connor-and-many-other-irishmen