The Anthony Bacon acrostic was found in a bundle of letters either written to him or from him. Note that the spelling isn’t exact for either his first or last name but that there is no doubt as to the person indicated. As the Friedmans acknowledge “it should also be stressed that spelling in these days was erratic”. An interesting observation here is how in the first line Anthony Bacon is compared to the mythical bird the “Phoenix”, also known as the “Arabian bird”. In the Shakespeare play of Anthony and Cleopatra, on page 352, we find the line:
Agri. Oh Anthony, oh thou Arabian Bird!
‘Anthonio’ and Phoenix are also mentioned together in Twelfth Night, pg. 272. The only other Shakespeare character I found directly associated with the Arabian bird was the female protagonist Imogen in Cymbeline, unless one counts the baby Elizabeth in Henry VIII.
Ben Jonson, the playwright (and longtime friend of Francis Bacon) also used acrostics. He used a very obvious one in his play The Alchemist and another obvious acrostic in his poem To Doctor Empiric.
There are many less obvious acrostic patterns than the basic first letter of each line examples. Some use the last letter of each line. Some use the first letter of the first line, then the second letter of the second line, then the third, fourth, etc. Another has used this and in addition used the last letter of the first line, the second to the last letter of the second line, and on. Another variation is to reverse the letters, that is, starting at the bottom of the poem or text. Another variation described in the Wikipedia article is of one that used the first letter of each Chapter in a book -- http://en.wikipedia.org/wiki/Hypnerotomachia_Poliphili
The Friedmans said that “There may be any number of varieties of acrostic” but also, in their view “...but each has one property in common. In every acrostic, the rules for selecting the letters of the secret text are invariable, and the selection follows a fixed pattern; moreover, the selected letters are chosen in a particular order, and the rules for setting them out in the form of a text are rigid and inflexible.”[p. 98]
They then cite the pitfalls of some of the Baconian acrostics he examined. Mostly they focus on what was called a ‘string cipher’ or acrostic variation that was part acrostic and part anagram and that may include abbreviations and Latinization. They fault these saying: “The letters and syllables are not always taken from the beginnings of lines, and each ‘signature’ is so short that it can only plausibly be explained as the outcome of chance.” [p. 129]