[2] The church was named in honor of Saint Josaphat, who was born circa 1580 as John Kuncevic in Vladimir, a village of the Lithuanian Province of Volhynia (then a part of the Polish Kingdom begun under the Jagiellonian dynasty), and who rose to increasing positions of authority within the church after professing his faith.

Murdered in Vitebsk (Belarus) on November 12, 1623, while working to reunify the diocese he had been assigned to lead, he was declared "Blessed" by Pope Urban VIII in May 1643.

On November 25, 1963, during the Second Vatican Council, the remains of Saint Josaphat were officially laid to rest at the altar of St.

In the section of Philadelphia called Manayunk, there was a great need for workers in steel, wool and paper plants.

[5] Father Tomiak, who had been ministering to the poor as a member of the Congregation of the Missionary Fathers of Saint Vincent de Paul when he was drafted into the military and sent to the front to nurse soldiers during the Franco-Prussian War, and had been ordained in 1893 at the age of 50 after resuming his studies in Rome post-war, had emigrated to America shortly thereafter.

During his 11-year tenure, he launched a parish parochial school (soon after arriving) and invited the Bernardine Sisters in as faculty, and founded two orphanages (one in West Conshohocken and the other in his native Wolsztyn).

Soon after beginning work, Guzik determined that the existing school building was no longer adequate, raised $40,000 to build a "yellow brick eight-room school," and then invited the Bernardine Sisters to return as faculty before making the decision to return to Poland.

Among his successes were the addition of 12 classrooms to the school building between 1927 and 1928, the launch of high school classes in 1939 (the first Polish pastor to achieve this milestone), the construction of a new, $130,000 rectory in 1949, and the construction of a new church building at the corner of Silverwood and Cotton streets with a spacious hall below the structure, which was dedicated on March 16, 1958, by the Most Reverend John F. O'Hara, C.S., D.D., Archbishop of Philadelphia.

Prior to his death on August 3, 1967, he was able to inspire his congregation to build a new convent for the sisters who served the parish and pay off the high school's tuition debt.

[8] In 1973, St. Josaphat's became the fourth Polish parish in the Archdiocese of Philadelphia to celebrate its 75th anniversary Diamond Jubilee.

The Reverend Monsignor John Wendrychowicz, the pastor of Saint Josaphat Parish at the time, informed parishioners of the decision in Masses held during the weekend of April 25, 2005, noting that he had also informed teachers and families of the children attending the school he had secured support from the Parish Pastoral and Finance Councils to request permission from Cardinal Justin Rigali, Archbishop of Philadelphia, to close the facility.