Meaning of 'was to become possible' ?

[Aquamarine]

What does the 'was to become possible' in this phrase mean ?

Jan Micker’s 1652 masterwork Bird’s Eye View of Amsterdam, painted by the artist long before such a vantage point was to become possible, ...

Source : CAT exam. Full question below :


Jan Micker’s 1652 masterwork Bird’s Eye View of Amsterdam, which had been painted long before such a vantage point became possible, features spatial relationships that are more subtle and intricate than in most other seventeenth-century Dutch paintings.
A. which had been painted long before such a vantage point became possible, features spatial relationships that are more subtle and intricate than in
B. painted by the artist long before such a vantage point was to become possible, and featuring spatial relationships that are more subtle and intricate than those in
C. which the artist painted long before the possibility of such a vantage point, featuring spatial relationships that are more subtle and intricate than the ones in
D. painted long before the possibility of such a vantage point, with spatial relationships that are more subtle and intricate than the ones in
E. painted long before such a vantage point became possible, features spatial relationships that are more subtle and intricate than those in

[rte.sushil]

was to become....means it was about to happen in the past

e.g. I was about to become a rider.....means very close to become a rider but couldn't

[jlucero]

Correct.