a h-aon deag fichead An Bhealtaine, De' Luan(31 May, Monday),or in Welsh, un ar ddeg ar hugain Mai, Dydd LLun Before going any further here are some corrections. First, I am informed that the C.S.Gilbert cited in the calendar probably was not the fellow involved in operettas. This is from the bio section of the New York Opera company's website: Born in London on November 18, 1836, W.S. Gilbert began his career as a civil servant, and was admitted to the bar...But he soon turned to writing works for the stage. The first joint effort of Gilbert and Sullivan was Thespis, written in 1871. (See http://www.nycopera.com/education/g&sbio.html) Now who was this C.S. Gilbert??? Secondly, I find that there are several ways to write "thirty" in Gaelic. My Irish tourist guide says that it is "triocha". However, Celtic numbering tends to count in terms of twenties, e.g. "four and twenty blackbirds" or " four score(4x20) and seven years ago". Mathematics from the Birth of Numbers by Jan Gullberg and my copy of MacAlpines Pronouncing Gaelic Dictionary by MacLaren supports this. It appears that Irish may have been simplified to get away from the twenties counting. If anyone out there can verify that I would be glad to learn. Anyway, thirty under the twenties system is "deich fichead". thar is, ten and twenty. The same applies to Welsh which would be "deg ar hugain" Seventy is, get this, deich is tri fichid, or, 10 and three twenties. By the way, if you are a numbers person like me (civil engineer) you might find the Gullberg book interesting. It was published in 1997 by W.W.Norton and Company a h-aon deag fichead An Bhealtaine, De' Luan(31 May, Monday),or in Welsh, un ar ddeg ar hugain Mai, Dydd LLun In 1257 Welsh forces under Meredudd ap Ryys and Meredudd ab Owain amushed a force of English and Welsh collaborators killing 3,000 in a battle at Pontargottn that lasted three days.