Molly Allgood
O'Neill , Máire
    1887-1952
    Nationality: Irish
    Occupation: actress

James Butler
Duke of Ormonde ,    
    1610-1688
    Nationality: Irish
    Occupation: nobility

Capuchin Order
    -
    Nationality:
    Occupation:

Katharine F Clausen
O'Brien , Katharine    
    1886-1936
    Nationality: Irish
    Occupation: artist

Thomas Fitzgerald
Silken Thomas
Lord Offaly ,
    1513-1537
    Nationality: Irish
    Occupation: leader

Franciscan Order
    -
    Nationality:
    Occupation:

Othon Friesz
Othon , Achille-Émile
    1878-1949
    Nationality: French
    Occupation: artist

Lady Morgan
Owenson, Sydney    
    1776-1859
    Nationality: Irish
    Occupation: writer

Sean O'Boyle
    1908-1979
    Nationality: Irish
    Occupation: musicologist

Conor Cruise O'Brien
    1917-
    Nationality: Irish
    Occupation: writer, politician, editor

Vincent O'Brien
    -
    Nationality: Irish
    Occupation: conductor

Donal O'Brien
    -
    Nationality: Irish
    Occupation: leader

Lucy O'Brien
    -
    Nationality: Irish
    Occupation: artist

Killy Wilmer O'Brien
Wilmer, Pamela Kathleen Helen   
    1910-1982
    Nationality: Irish
    Occupation: artist

Dermod O'Brien
    1865-1945
    Nationality: Irish
    Occupation: artist

Catherine O'Brien
O ' Brien , Catherine Amelia    
    1881-1963
    Nationality: Irish
    Occupation: artist

Mabel O'Brien
    -1942
    Nationality: Irish
    Occupation:

Earl of Inchiquin, Murrough O'Brien
    1614-1674
    Nationality: Irish
    Occupation: military, politician

Cathal O'Byrne
    1876-1957
    Nationality: Irish
    Occupation: writer

Diarmuid O'Callaghan
    -
    Nationality: Irish
    Occupation: artist

Lucius O'Callaghan
O Callaghan , Lucius
    1877-1954
    Nationality: Irish
    Occupation: Art Historian

Margaret O'Callaghan
    -
    Nationality:
    Occupation: academic

Turlough O'Carolan
    1670-1738
    Nationality: Irish
    Occupation: composer, musician

Margaret O'Carroll
    1405-1451
    Nationality: Irish
    Occupation: leader

Sean O'Casey
    1880-1964
    Nationality: Irish
    Occupation: writer

Daniel O'Connell
    1775-1847
    Nationality: Irish
    Occupation: politician, revolutionary

Faly O'Connor
    -
    Nationality: Irish
    Occupation: leader

James Arthur O'Connor
    1792-1841
    Nationality: Irish
    Occupation: artist

Rory O'Connor
    1883-1922
    Nationality: Irish
    Occupation: revolutionary

Liam O'Connor
    -
    Nationality:
    Occupation: writer

Ulick O'Connor
    1929-
    Nationality: Irish
    Occupation: writer

Joseph O'Connor
    -
    Nationality: Irish
    Occupation: writer

Roderick O'Connor
    -1118
    Nationality: Irish
    Occupation: leader

John O'Connor
    1913-
    Nationality: English
    Occupation: artist

Cathal O'Connor
    1150-1224
    Nationality: Irish
    Occupation: benefactor

Eugene O'Curry
    1794-1862
    Nationality: Irish
    Occupation: scholar

James Augustine O'Dea
    -
    Nationality:
    Occupation:

Jimmy O'Dea
    1899-1965
    Nationality: Irish
    Occupation: actor

Brian O'Doherty
Ireland , Patrick
    1934-
    Nationality: Irish
    Occupation: critic

Peadar O'Donnell
    1893-1986
    Nationality: Irish
    Occupation: revolutionary, writer

Manus O'Donnell
    -1563
    Nationality: Irish
    Occupation: nobility

John O'Donovan
    1806-1861
    Nationality: Irish
    Occupation: historian

John O'Donovan
    1806-1861
    Nationality: Irish
    Occupation: historian

Frank O'Connor
O'Donovan, Michael    
    1903-1966
    Nationality: Irish
    Occupation: writer, director, revolutionary

Eimar O'Duffy
    1893-1935
    Nationality: Irish
    Occupation: writer

Eoin O'Duffy
    1892-1944
    Nationality: Irish
    Occupation: soldier

Peregrine O'Duigenan
O'Clery , Peregrine
    -
    Nationality: Irish
    Occupation: historian

Sean O'Faolain
Ó Faoláin , Séan    
    1900-1991
    Nationality: Irish
    Occupation: writer

Liam O'Flaherty
    1896-1984
    Nationality: Irish
    Occupation: writer

Robert O'Flaherty
    1884-1951
    Nationality: American
    Occupation: filmaker

Fergal O'Gara
    -
    Nationality: Irish
    Occupation: benefactor

Eugene O'Growney
    1863-1899
    Nationality: Irish
    Occupation: linguist, priest

Frank O'Hara
    1926-1966
    Nationality: American
    Occupation: writer

P S O'Hegarty
O'Hegarty, Patrick Sarsfield   
    1879-1955
    Nationality: Irish
    Occupation: collector

Kevin O'Higgins
    1892-1927
    Nationality: Irish
    Occupation: politician

Sean Thomas O'Kelly
    1883-1966
    Nationality: Irish
    Occupation: leader

John O'Leary
    1830-1907
    Nationality: Irish
    Occupation: revolutionary

Power O'Malley
    -
    Nationality:
    Occupation:

Cathal O'Malley
    -
    Nationality: Irish
    Occupation:

Ernie O'Malley
    1898-1975
    Nationality: Irish
    Occupation: writer, revolutionary

Fearfeasa O'Maolchonaile
    -
    Nationality: Irish
    Occupation:

John O'Neill
    -
    Nationality: Irish
    Occupation:

Eamonn O'Neill
    -
    Nationality: Irish
    Occupation:

Hugh O'Neill
    -
    Nationality: Irish
    Occupation:

Eugene O'Neill
    1888-1953
    Nationality: American
    Occupation: writer

Chief O'Neill
    -
    Nationality: Irish
    Occupation: composer

J J O'Neill
    1886-1953
    Nationality: Irish
    Occupation: administrator, writer

Owen Roe O'Neill
    1590-1649
    Nationality: Irish
    Occupation: military

Mary Devenport O'Neill
    1879-1967
    Nationality: Irish
    Occupation: writer

Brian O'Nolan
    1911-1966
    Nationality:
    Occupation: writer

Conal O'Riordan
Connell , Norreys
    1874-1948
    Nationality: Irish
    Occupation: writer

Fergus O'Ryan
    1911-1989
    Nationality: Irish
    Occupation: artist

Kevin Roantree O'Shiel
    -
    Nationality: Irish
    Occupation: politician

Seumas O'Sullivan
Starkey, James Sullivan   
    1879-1958
    Nationality: Irish
    Occupation: writer, editor

Martin O'Sullivan
    -
    Nationality:
    Occupation:

Sean O'Sullivan
    1906-1964
    Nationality: Irish
    Occupation: artist

Saint Laurence O'Toole
    1128-1180
    Nationality: Irish
    Occupation: religious figure

William O'Toole
    -
    Nationality:
    Occupation:

Saint Laurence O'Toole
    -
    Nationality:
    Occupation:

Sean O Cathain
Ó Cathaín , Sean    
    -
    Nationality: Irish
    Occupation: writer, translator

Micheal O Clerigh
O Clérigh , Míchéal
    1590-1643
    Nationality: Irish
    Occupation: historian, writer

Padraic O Conaire
O Conaire , Pádraic    
    -
    Nationality: Irish
    Occupation:

Tomas O Deirg
    -
    Nationality: Irish
    Occupation: educator

Aodh Ruadh O Domhnaill
O' Donnell , Red Hugh   
Hugh , Red    
    1571-1602
    Nationality: Irish
    Occupation: leader

Donogh O Donoghue
    -
    Nationality: Irish
    Occupation: benefactor

Eamon O Gallchobhair
    -
    Nationality: Irish
    Occupation: historian

Domhnall O Murchadah
Murphy , Donal
Ó Murchadah , Domhnall
    1914-1991
    Nationality: Irish
    Occupation: artist

Eoghan O Suillebhain
O Síillebháin , Eoghan    
O'Sullivan , Egan    
    -
    Nationality: Irish
    Occupation: writer

Jacques Offenbach
Eberst , Jacob
    1819-1880
    Nationality: German, French
    Occupation: composer

Daithi O hOgan
Ó hÓgán , Daithí    
    -
    Nationality: Irish
    Occupation: academic

Oireachtas
    -
    Nationality:
    Occupation:

Grand Duchess Olga
    -
    Nationality:
    Occupation:

Olin Library
    -
    Nationality:
    Occupation:

Sir Henry Francis Oliver
    1865-1965
    Nationality: English
    Occupation: military

Alessandro Oliverio
    1500-1544
    Nationality: Italian
    Occupation: artist

Omphile
    -
    Nationality: Irish
    Occupation: leader

John Opie
    1761-1807
    Nationality: English
    Occupation: artist

Giuseppe Orioli
    1884-1942
    Nationality: Italian
    Occupation: antiquarian, publisher

Iris Orpen
    -
    Nationality: Irish
    Occupation: artist

Bea Orpen
    1913-1980
    Nationality: Irish
    Occupation: artist

Sir William Orpen
    1878-1941
    Nationality: English
    Occupation: artist

Clarice Orsini
de Medici , Clarice    
    1450-1488
    Nationality: Italian
    Occupation: nobility

Joe Orton
    1933-1967
    Nationality: English
    Occupation: writer

Walter Osborne
    1859-1903
    Nationality: Irish
    Occupation: artist

Shotaro Oshima
    1899-
    Nationality: Japanese
    Occupation:

Roland Oudot
    1897-
    Nationality: French
    Occupation: artist

Roland Oudot
    1897-
    Nationality: French
    Occupation: artist

Ovid
Naso, Publius Ovidius   
    43-17
    Nationality: Italian
    Occupation: writer

Wilfred Owen
    1893-1918
    Nationality: English
    Occupation: writer

Oxford University
    -
    Nationality:
    Occupation:

Padraic O Siochfhradha
Seabhach , An
O Siochfhradha , Pádraic
    1883-1964
    Nationality: Irish
    Occupation: writer, politician

John Sullivan
O'Sullivan , John    
    1877-1955
    Nationality: Irish
    Occupation: singer

University of Oxford
    -
    Nationality:
    Occupation:

Conde de Olivares
    1587-1645
    Nationality: Spanish
    Occupation: leader

Adriaen van Ostade
    1610-1684
    Nationality: Dutch
    Occupation: artist

Aogan O Rathaille
Ó Rathaille , Aogán    
O ' Reilly , Egan    
O'Rahilly , Egan    
    1675-1729
    Nationality: Irish
    Occupation: writer