  We derive rotation free Lorentz Transformation (LT) between two inertial
reference frames without using the second postulate of Einstein, i.e., we do
not assume the invariant speed of light (in vacuum) under LT. We find a general
transformation rule between two inertial frames where a speed, invariant under
that transformation, arises naturally. This idea first came into light by
Mathematician Ignatowski [1] around the year, 1910. Without loss of novelty,
here we present our derivation while reviewing more recent literature in this
subject.
