The Jerusalem Cross has several meanings associated with it.
It has been said the the four smaller crosses are the disciples and the larger central cross is Christ. The five crosses have been said to also represent the five wounds of Christ. The smaller crosses have been interpreted as meaning the four corners of the world, with Christ the center.
The Jerusalem Cross is also known as the Crusader's Cross. The cross dates back to the 11th and 12th century when the Crusaders captured Jerusalem in 1099, establishing Christianity in the area, which up until that time had been under Muslim control.
This design reminds us to bring the Gospel to the world, complete with Matthew 28:19 in Latin:
Euntes ergo docete omnes gentes: baptizantes eos in nomine Patris et Filii et Spiritus Sancti.
"Go, therefore, make disciples of all nations: baptize them in the name of the Father and of the Son and of the Holy Spirit."