1.  Marriage Record:

2.  1870 Census Index/Images (online at Genealogy.com; Image #20 of 68):  Pittsburgh P.O., Pittsburgh (Ward 3), Allegheny Co., PA, Roll 1295 (Book 1), p. 455B, PN 20, 169/168, enumerated 25 Jul 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):¤•

Stroup W H	26	M	W	Keeps Tavern		10,000	Penna
______ Nellie W	19	F	W	Landlady			New York
Radley Thomas	25	M	W	Bar Tender			Penna
Stroup John	17	M	W	Do			Do
______ George	20	M	W	At Home			Do
______ Peter	65	M	W	Old Gent			Do
Alden H C	34	M	W	Bar Tender			Massachusetts
Warren Harry	28	M	W	Man of Billiard Room			Canada
Stroup Alexina	51	F	W	Old Lady			Penna
Griffen Mary	19	F	W	Dom Servant			Do
Warren Elmira	19	F	W	Boarding			Do
______ William F	2	M	W				Do
Allen Nelson	19	M		Dom Servant			Virginia

Peter & Alexina STROUP are Horatio's parents; John and George STROUP are Horatio's brothers. 

3.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  can't find.

4.  1890 Census:  the 1890 Census Population Schedules were destroyed.

5.  1900 Census Every-Name-Index/Images (online at Ancestry.com):  not found.