The S-300P is a mobile system, that can be used in all weather conditions and that is able to engage enemy aircraft, at all altitudes, as well as flying objects with low Radar Cross Section, incoming at low altitudes (like cruise missiles). The upgraded S-300PS is also able to engage ballistic missiles, and it is the only variant known to have been equipped with nuclear warheads. The Western counterpart to the S-300P is the MIM-104 Patriot.
Development of the S-300P began in the year 1967, with the aim of creating a more capable replacement for the aging SA-1 Guild systems and which should later replace the SA-2 Guidelines and SA-3 Goas. The system entered service with the Soviet Armed Forces in the year 1978.
The last variant of it, the S-300PMU-2 was introduced in 1999. And because these two newer systems, the S-300PMU-1/2 showed many differences to their predecessors, they were named SA-20 Gargoyle by the NATO in 2003.