Maybe I misunderstood the great commission, or maybe I am only familiar with the kind of Christianity practiced by the Christians I have known in my lifetime.

Maybe I misunderstood the great commission, or maybe I am only familiar with the kind of Christianity practiced by the Christians I have known in my lifetime. Perhaps saying that the great commission calls on every Christian to proselytize is not universally accepted among Christians. As I said, I cannot really comment on Christian perspectives because I am not a Christian. I do not think there is much doubt that Christianity is a religion that actively seeks converts, and Eastern Orthodox churches are not an exception (they have missionaries too). It may not be the central motivation of every church, and it may not be required of every individual Christian, but proselytizing of some kind is a requirement of Christianity. It is doubtful that Jewish proselytizing occurred to any significant degree under Christian or Muslim rule, which would have been the majority of the lands where Jews lived during the medieval period. It was made illegal by various emperors, kings, and councils. Jews were already suffering the persecution of Christian rule toward the end of the classical period -- among other things, the Sanhedrin was abolished (its last act was the creation of a fixed Jewish calendar; the biblical system you mentioned was based on observing the moon and having religious authorities make announcements of those observations, which could not continue without the Sanhedrin). Judaism remains open to conversion by people who want to convert, but there have be no active efforts to find or win converts for at least 1000 years, and I suspect even longer than that.