Messiah was to come after the 69th sabbath cycle.
The unit of
time-measurement appears to be cycles of sabbatical years,
here translated ‘sevens,’ traditionally
The starting point seems to
be the command of King Artaxerxes 1 in his
20th year (445 BC).
The sabbatical cycle in
which this starting point falls is 449-442
Using the usual inclusive
method of counting, the 69th cycle is