955 B
General Information:
Verses 19 and 20 tell what is going to happen to John but has not happened at this time. (See: rc://en/ta/man/jit/writing-background)
Herod the tetrarch
Herod was a tetrarch, not a king. He had only limited rule over the region of Galilee.
When Herod the tetrarch had been reproved
It is implied that John reproved Herod. This can also be translated with an active form. Alternate translation: "When Herod the tetrarch had been reproved by John" or "When John reproved Herod the tetrarch" (See: rc://en/ta/man/jit/figs-explicit and rc://en/ta/man/jit/figs-activepassive))
for marrying his brother's wife Herodias
"because Herod married Herodias, his own brother's wife." This was evil because Herod's brother was still alive. This can be stated clearly. Alternate translation: "because he married his brother's wife, Herodias, while his brother was still alive" (See: rc://en/ta/man/jit/figs-explicit)