GenealogiCal is a calendar of significant genealogical and historical events, with particular focus on some of the counties in which I am interested. I hope to update this regularly and would welcome any corrections and/or additions that you have If giving me suggestions, can you include the source of the information so that I can reference it. Please note that at the time of writing, October 1999, it is still in its infancy - I expect to add to it significantly over time.

I have copyrighted the term GenealogiCal in the context of which is used here (i.e. to mean a genealogical calendar) in order to prevent unauthorised copying my idea or work.
 

c1200	Welshman Geraldus Cambrensis' illustrated Topographia Hiberniae which includes a very early map of Ireland3
1235	Norman Invasion of Connacht1
1245	The Norman lord, Maurice Fitzgerald builds castle on Garvogue, founding Sligo town in the process1
1252-53	Foundation of Sligo Abbey2
1564	Gerardus Mercator's map of Ireland, one of the first reasonably detailed maps of the country3
1588	The Spanish Armada
1590	The potato was introduced to Ireland1 (by Sir Walter Raleigh according to tradition)
1594	Opening of Trinity College5
1601	The Battle of Kinsale - Irish & Spanish forces against English forces5
1607	The Flight of the Earls (The Great O'Neill, Maguire & O'Donnell to Spain)5
1610	Commencement of widespread plantation of Ulster5
1633-35	Strafford Survey1
1654-1656	Civil Survey of Ireland (includes frequency of most common names in each parish plus population figures for each townland).
1664-1666	Hearth Money Rolls, recording heads of households paying Hearth Tax. Not all counties covered6
1665	William Petty's Hiberniae Delineatio, the first Atlas of Ireland with 36 maps - 1 national, 4 provencial and 31 county maps3
1796	Spinning Wheel Lists, recording name and parish of anyone who received a free spinning wheel under a Government grant6
1816	A Statistical Account or Parochial Survey of Ireland, William Shaw Mason
1823-38	Tithe Applotment Records, which record the head of each household which paid tithes.
1824	Ordnance Survey office set up3
1829	Catholic Emancipation4
1838	Irish Poor Law Act, which established 130 Poor Law Unions throughout Ireland1
1839	The Big Wind
1845	Commencement of State registration of non-Catholic marriages6
1845-48	The Great Famine
1846	Completion of first Ordnance Survey of Ireland, with 1906 maps eachcovering 24 sq. miles3
1847	Number of Poor Law Unions increased from 130 to 162, including 2 additional ones in Co. Sligo - at Tubbercurry and Dromore West1
1854-57	Griffith's Valuation
1861	Last public hanging in Sligo - a Mathew Phibbs from Ballymote1
1864	Commencement of State registration of Catholic marriages6
1901	Earliest available full census of Ireland
1911	Latest publicly available census of Ireland
1916	The Easter Rising
1920-21	The War of Independence

¹ "In Sligo Long Ago - Aspects of Town and County over Two Centuries" - John C. Mc Ternan,1998 (ISBN 0952059460 
² "Sligo Abbey - Historical and Descriptive Notes on the Dominican Friary of Sligo" - Irish Stationery Office 
³ "The Mapping of Ireland" - article from Aer Lingus in-flight magazine - Cara, Nov/Dec 1998 
⁴ "The Birth of Modern Ireland" - Tierney & MacCurtain, 1969 
⁵ "Ireland 1478-1610" - M.E. Collins, 1980
⁶ "Tracing Your Irish Ancestors" - John Grenham, 2nd Edition, 1999