  Rao (1948) introduced the score test statistic as an alternative to the
likelihood ratio and Wald test statistics. In spite of the optimality
properties of the score statistic shown in Rao and Poti (1946), the Rao score
(RS) test remained unnoticed for almost 20 years. Today, the RS test is part of
the ``Holy Trinity'' of hypothesis testing and has found its place in the
Statistics and Econometrics textbooks and related software. Reviewing the
history of the RS test we note that remarkable test statistics proposed in the
literature earlier or around the time of Rao (1948) mostly from intuition, such
as Pearson (1900) goodness-fit-test, Moran (1948) I test for spatial dependence
and Durbin and Watson (1950) test for serial correlation, can be given RS test
statistic interpretation. At the same time, recent developments in the robust
hypothesis testing under certain forms of misspecification, make the RS test an
active area of research in Statistics and Econometrics. From our brief account
of the history the RS test we conclude that its impact in science goes far
beyond its calendar starting point with promising future research activities
for many years to come.
