Happy Feria VI in Parasceve, or Good Friday. I know this question has been bothering you for a while, and I'm afraid the Catholic Encyclopedia isn't much help:

The origin of the term Good is not clear. Some say it is from 'God's Friday' (Gottes Freitag); others maintain that it is from the German Gute Freitag, and not specially English. Sometimes, too, the day was called Long Friday by the Anglo-Saxons; so today in Denmark.

According to my simple understanding of Christian dogma, the original Good Friday was not in fact humanity's finest hour. If torturing and killing God Himself is your idea of "good," I'd hate to be around on one of your bad days.

Moving on, later in the Encyclopedia's description of the offices and sacraments of Good Friday, we come across the following:

When this [the Passion according to St. John] is finished, the celebrant sings a long series of prayers for different intentions, viz. for the Church, pope, bishop of the diocese, for the different orders in the Church, for the Roman Emperor (now omitted outside the dominions of Austria)...

Whoa there! You're saying that in Austria, they still pray for the Roman Emperor on Good Friday? That's what I thought it said, but alas, it's too good to be true: The Catholic Encyclopedia was published in 1907, when an Austrian Imperator indeed still ruled these Czech lands and many others.

Still, there's something strange here. The term "Romanorum Imperator" or "King of the Romans" was retired, once and for all, with the official dissolution of the Holy Roman Empire in 1806, following the Battle of Austerlitz at what is now Slavkov near Brno in December 1805. As late as 1806, the Austrian 20 Kreuzer coin still read "FRANC.II. D.G. ROM. ET. HAER. AUST. IMP. GER. HUN. BOH. REX. A.A. D. LOTH. VEN. SAL., or something along the lines of, "Francis II, By the grace of God Emperor of the Romans And Hereditary Emperor of Austria, King of Germany, Hungary and Bohemia, Archduke of Austria, Duke of Lorraine, Venice and Salzburg."

According to my understanding, the Austrians abolished the title in part so that Napoleon could never lay his grubby little French hands on it.

So... Were Czech Catholics really still saying Easter prayers for the so-called Roman Emperor one hundred years later, when the Catholic Encyclopedia was published?

FRANK-ly, it appears so!