1890 Jul 18 Born Cambridge
1891 census at Victoria Road, Chesterton, Cambridge
1901 census at 14, Park Terrace, Cambridge
1911 census at The School House Wragby Road Lincoln, where he is an Assistant Schoolmaster
1915 Mar 5. Landed in France
1916 Aug 8. The undermentioned Warrant Officers, non-commissioned officers and men to be temporary Second Lieutenants (on probation), with effect from the dates shown: — R War. R. - Pte. R. H. Costigan, from A.S.C.
1917 Jun 21. Training Reserve. Temp. 2nd Lt. R. H. Costigan, from R. War. R., to be temp. 2nd Lt. 21 June 1917, with seniority 8 Aug. 1916.
1917 Nov 1. R Warwickshire Reg. The undermentioned temp. 2nd Lts. to be temp. 2nd Lts. (attd.), retaining present seniority:— R. H. Costigan, from Trg. Res. 1 Nov.
1920 Dec 11. R War. R. Temp. Lt. R. H. Costigan relinquishes his commission on completion of service, and retains the rank of Lt.
1921 Jan 23 Joined ADRIC with service no 1594. O Coy
1921 Feb 13 Posted to N Coy After Trim as a Section Leader
1922 Jan 14 Discharged on demobilisation of ADRIC
1923 Jul/Sep Married in Coventry to Aileen J M Miller
1942 Apr/Jun died Lambeth, London aged 52 - suicide