By the Matin Church when O. ent. V. 6932

This is actually a typographical error. It should read "by the Latin Church when ʘ ent. V" (where Latin refers to the Catholic church).The ʘ and "curly V" are, respectively, astrological symbols for the Sun and the constellation Aries.

The phrase "Sun enters Aries" refers to the appearance that the Sun is passing into the constellation, a phenomenon that occurs around 21 March - the Northern Equinox. In Western Christianity the date of Easter is (partly) determined around this occurrence.

More importantly, however, the Northern Equinox (and Spring more broadly) is considered to coincide with the Biblical creation of the world - hence why the "Latin" reckoning of creation would be calculated from the traditional date marking Spring's beginning.

"W.W." was William Winstanley (c.1628-1698), an author and poet who also wrote under the pseudonym "Poor Robin". He was the compiler of An Episcopal Almanack, published between 1674 and 1678, which incorporated a calculation of the year of creation into its title page.

The inclusion of such dates was a commonplace in almanacs of this period and can be traced back to John More's A Table from the Beginning of the World (1593) and to the addition of "A Brief Chronologie of sundry Memorable Accidents" in the Jonathan Dove Almanac in the 1620s.

These systems antedate Ussher's calculations. The one used by "Jonathan Dove" dates the creation to 3949 BC and that used by More to 4009 BC. These variances are not untypical of the more than 100 known attempts to establish a Biblical chronology of the world; all such calculations require interpretation of some vague passages. Even the creationist website I consulted on this matter admits that "The calculations are not as straightforward in the Bible as one might hope."