While researching information for this page, I found many internet sites that give a variety of stories and pictures on the Maltese Cross, St. Florian & the Star of Life. The common denominator to most of them is that the cross has undergone some revisions over the years, but here goes my abridged interpretation/versions.
The Knights of St. John (now commonly known as the Knights of Malta) can trace their history to a group of monks attached to a hospice in the holy lands. The monks were known as the Freres Hospitaliers de St. Jean de Jerusalem. The symbol was adopted by the brotherhood of the hospital around 600 A.D. as a white, eight pointed emblem worn on the left breast of their black robes after the merchants of Amalfi (Campania, Italy) helped them rebuild the hospital.

Over time, the monks began to offer armed escort to travelers as they passed through perilous territory & evolved into a military order who then participated in crusades. After their incorporation as a military order, the knights continued to run the hospital which gained them respect & prestige. The battle dress for knights of the military order included a white cross on a red background and first became a "badge" in 1023.

With the political climate & persecution being what it was, the Knights of St. John moved to the island of Malta in the Mediterranean Sea in 1522-1523.
During a particular crusade against the Saracens to take back the holy land, the Knights of St. John (Malta) encountered a weapon unknown to Eurpoean warriors - FIRE.

As the knights advanced on the city, the Saracens hurled glass jars of Naphtha into the crowd followed by flaming torches that ignited the highly flammable liquid caused hundreds of them to be burned to death. Those not directly in the inferno went to the rescue & aide of their comrades to extinguish the fires & save lives. Noted by the others in the crusade, these heros were presented with a badge of honor.

That badge of honor is what we know today as the Maltese Cross.
St. Florian - The patron saint of firefighters.

Florian was born in Cetium, Austria about 250 A.D. and avanced through the ranks of the Roman army with hard work & determination. After advancing through the ranks and capable of handling things, the Emperor appointed Florian to a high administrative post in Noricum (now Austria).

The Emperor ordered all Christians in the area contolled by Florian to be punished through burning of buildings & books, imprisonment & finally sacrifice to the Roman gods. Citing that he too was a Christian, Florian refused to do so led to the fear that he would lead others to rebel. Sacrificing himself as the army began to "round up" the Christians, Florian stood atop a funeral pyre & challenged the Romans to light the fire stating that he would climb to heaven on the flames. Fearing his words true, Florian was then flogged & drown in the Enns river.

But because of his stand & resistance to death by fire, St. Florian became the protector of firefighters worldwide.
The Star of Life

Designed by Leo R. Schwartz, EMS Chief for the NHTSA in 1973 after the American National Red Cross felt that the "Omaha Orange" cross on a square white background too closely resembled their symbol.

The six barred cross was adapted from the medical identification symbol of the AMA. Each of the blue bars represents the six functions of EMS. Detection. Reporting. Response. On scene care. Care in transit & Transfer to definitive care.

The snake & staff in the center portray the staff of Asclepius who according to Greek mythology was the son of Apollo & learned the art of healing from the centaur Cheron.
Symbolic History
St. Florian's Prayer

St. Florian, Heaven’s patron of firefighters,
who once was dedicated to the services
of your fellowmen as an official in the
Army of Rome, look with kindly and
professional eye upon your earthly force,
desirous of the preserving of our fellowmen
from the dangers to life and property.
Give us cool heads, stout hearts, strong muscles
an instinct for prudent investigation and
wise judgment.

Make us the terror of arsonists, the friends of
law-abiding citizens, kind to the frightened,
polite to the bores, strict with lawbreakers,
and obstinate to temptations.

In troubles give us strength to be efficient,
in times of great danger, give us the ability
to be calm and enable us to impart assurance
to those who verge on panic.

You know, beloved St. Florian, from the
sacrifice of your own life for the sake of
your faith, that the fireman’s lot on earth
is not always a pleasant one, but your
sense of duty that so pleased God, your
courageous strength that so over-whelmed
the devil and your saintly self-control,
give us inspiration.

Make us as fearless in practicing the laws
of God as we are brave in protecting the
lives and property of our fellowmen, and
when we answer our final alarm, enroll
us in your Heavenly force, where we will be
as proud to protect the throne of God as
we have been to protect the city.