Theodore and John (d. 983) were Varangians, i.e., members of that ethnic group that includes today’s Norwegians, Swedes, and all that lot. In those days Varangians were a big presence in Kievan Rus’, which was on their primary trading route to Constantinople and all it represented (the Spice Road, the Mediterranean, Doner kebabs, etc.). Some of them were Christians, but most were pagans of the human-sacrificing variety—the kind you really don’t want to meet in a dark alley, light alley, market square, or anywhere else if you can avoid it.
After Svyatoslav (Olga’s son, see July 11) was killed by the Pechengs (which is fun to say—try it!), his lands were divided between his three sons, Oleg, Vladimir, and Yaropolk, the latter a Christian, albeit “of the Latin variety” (horrors). The Varangians manipulated Oleg and Yarapolk into a fratricidal war (the sources imply they were all unwilling), and when Oleg was killed, they pitted Yarapolk against Vladimir. The latter invited the former for a brotherly chat, but as he arrove he was ambushed and murdered. Vladimir then set up idols, and the human sacrifice thing started up.
Theodore and his beloved son John were Christians, and one day when the child sacrificers were stirring the tiles, John’s name was drawn (“evidently not by chance,” one source adds). When told of this, Theodore said, “Idols are just pieces of wood, and I worship the God who created heavens and earth and so on. No son of mine is going to be sacrificed by those devils.” Now, Theodore’s house, like many in the town, was built on pilings, and he stood at the top of the stairs and defied the pagans to take his son. “Send one of your gods to get him,” he taunted. Not in the mood to be taunted, they knocked away the pilings under the porch. Theydore and John fell, the pagans fell upon them, and soon they (Theodore and John) were dead, the first Christians to spill their blood on the holy soil of Rus’ (well, Ukraine nowadays).
A series of four wooden churches was built on the site, and each burned down (eleventh century, 1240, eighteenth century, 1936). (We avoid Monty Python references here.) I could find no evidence that it had been replaced again as of April, 2020. For reasons I cannot determine, the protomartyrs of the Rus’ are invoked by women who have suffered miscarriage.
John Gualbert (ca. 993–1073) was a Florentine nobleman, soldier, and playboy. When his brother Hugh was murdered, he set out to find the murderer and bring him to justice (or run him through, which was probably about as close to justice as it got at the time). He found the man in a narrow place in the mountains (on Good Friday—an important detail), drew his sword, and was about to deliver vengeance. As the murderer fell on his knees and prayed for God to accept his soul, John saw a vision of the crucifixion of our Lord, and heard (as it were) the words, “Forgive them, Father.” Moved to pity, he forgave the man, and Christ (in the vision) bowed his head in thanks.
John became a monk at the very next monastery, but left when the abbot died, either fearful he would be chosen to replace him, or disgusted by the concubinage, nepotism, and simony of the monastery (in particular) and the greater church (in general) (as one might well be). He founded another monastery, where he and his monks lived lives of strict austerity and charity to the poor. He was known for his wisdom, miracles, prophecies, and humility, and was credited by Pope Alexander II with stamping out simony in Italy (but not concubinage or nepotism? interesting omission). He is the patron of forest workers and park rangers.
 Clearly the Varangians couldn’t afford high-quality gold idols and had to make do with wooden ones.