Capitalisation to this extent wasn't around in Old English, and I didn't remember any in Chaucer's Canterbury Tales, but it seemed exist in some Shakespeare folios and not others, so it certainly hasn't been around since the beginning of written English.
I found this in an actual printed book, The Cambridge Encyclopedia of the English Language (David Crystal), p67, where the internet let me down. It's in the section about emerging orthography in the 16th Century:
Hart recommended his readers to use a capital letter at the beginning of every sentence, proper name, and important common noun. By the 17th century, the practice had extended to titles (Sir, Lady), forms of address (Father, Mistris), and personified nouns (Nature). Emphasized words and phrases would also attract a capital. By the beginning of the 18th century, the influence of Continental books had caused this practice to be extended still further (e.g. to the names of the branches of knowledge), and it was not long before some writers began using a capital for any noun that they felt to be important. Books appeared in which all or most nouns were given an initial capital (as is done systematically in modern German) - perhaps for aesthetic reasons, or perhaps because printers were uncertain about which nouns to capitalize, and so capitalized them all.
The fashion was at its height in the later 17th century, and continued into the 18th. The manuscripts of Butler, Traherne, Swift, and Pope are full of initial capitals. However, the later 18th-century grammarians were not amused by this apparent lack of discipline in the written language. In their view, the proliferation of capitals was unnecessary, and causing the loss of a useful potential distinction. Their rules brought a dramatic reduction in the types of noun permitted to take a capital letter.
It seems odd that Hart's recommendations on capitalisation should have taken root where his suggestions for phonetic spelling have fallen on deaf ears...
As Vitaly mentioned, this is a ligature: two letters are connected as if written without lifting the pen off the paper.
Ligatures were very common in the Middle Ages, and probably in Antiquity as well. Often the shape of a ligature changed away from its constituent letters with time, so as to render them unrecognisable in some cases. There were thousands of ligatures and abbreviations. Because ligatures usually take a bit less space than full letters, they were a means to save (expensive) paper; and the fact that scribes did not need to lift their pens off the paper as often saved time.
Ligatures are of course much less useful in print. Only some minor economy of space might conceivably be attained; the reason why some ligatures made it into print from time to time is probably tradition.
Generally there was no difference in meaning between ligature and full writing. It is true that certain ligatures are used much more often in one word than in another; the ligature &
, which stood for et
, was extremely common in the Latin word et ("and"), but significantly less so in other words, though it could be used in any word, such as car&
. Nevertheless, this ligature came to be associated with the word et so much that it carried over into other languages, even though the full word would be entirely different, like English and.
The ct ligature is quite natural in Medieval script; I have never seen it used with a specific meaning, and it cannot stand for an entire word on itself. That is why I believe it is applied mostly at random, i.e. it depends on the scribe.
Even so, it is possible that certain printers had specific conventions when to use it; these are unknown to me, and I bet nearly all readers wouldn't know the reason behind such conventions either, if such existed.
If you're interested in Medieval ligatures, you might like to browse Cappelli's dictionary of Latin abbreviations (or its English translation). Some of the Latin ligatures stood for letter combinations that were also useful in other languages and were often so used. Each language also developed some abbreviations and ligatures of its own, but the Latin ones were always the basis. Here is a page displaying the et ligature:
Here is a page of Latin manuscript, where you can see how many ligatures and abbreviations they used:
Nearly every mark or line indicates that something is left out or abbreviated. However, notice that this scribe didn't use the ct ligature, for no apparent reason; such variation is mostly arbitrary and depends on the scribe and his teachers.
Best Answer
This is called a catchword, and was used to
and also
Popular from all the way back in the medieval period, the practice faded from use with the introduction of industrial printing in the eighteenth century.