Location. The town of Malolos is situated by one of the estuaries of the same name, whose waters often flood the surrounding areas reaching as far as Paombong. The Paombong bounds it on the north; Sta. Isabel and Barasoain on the south; Bulacan on the west.

The Christianization of Malolos. After the Spanish missionaries evangelized Pampanga, the Augustinians went to Bulacan, starting with Calumpit. Fray Diego Ordoñez de Vivar and his companions landed in Kanalate in 1580 where they built a small chapel. Fray Diego Ordoñez us recorded as having established the first Christian communities. Later they moved further in land and build a bigger chapel in Kaingin. The Augustinians Chapter of June 11, 1580 accepted Malolos as a house of the Order. The parish was established. The construction of the stone church was started when the barrios of Atlag and Pinagbakahan were being born; and bridges connected the barrios of Atlag, Mambog, Santiago and Liyang to each other.

The Construction of the Church. The first convent and church, probably built of light materials, were finished in 1591, as the Catalogo attests. Fr. Roque Barrionuevo reconstructed and enlarged the buildings in 1691. In 1707, the principal of the town petitioned Governor General Doming Zabalburu de Echevarri to free the inhabitants of Malolos from rendering personal service and to allow them instead to work in the reconstruction of the church. Fr. Fernando Sanchez reconstructed the buildings with strong materials in 1734; Fr. Juan de Meseguer completed the construction in 1740; and Fr. Manuel Baceta applied the finishing touches in 1744.

The construction and the convent, therefore are two regularly constructed edifices. But a fire destroyed these edifices in 1813. Fr. Melchor Fernandez started reconstruction work in 1819. He constructed the bridge connecting Malolos with Barasoain. He also restored the convent and added some arches to the front and one more story to the belfry to accommodate the installation of the clock. It was consecrated by Francisco Alban, bishop of Nueva Segovia (Vigan) on October 18, 1826. At that time, it was the only church consecrated in the archipelago. The buildings were severely damaged during the earthquake of 1863; the walls cracked and the church and convent collapsed from the middle downwards. Fr. Ezequiel Merino restored them between the years 1859 to 1872. The convent was damaged again during the earthquake of 1880 and Fr. J.M. Tombo restored it in 1883. Fr. Felipe Garcia completed its restoration.

The Convento becomes the Presidential Palace. It was on the noon of September 10, 1898 when General Emilio Aguinaldo and his men arrived at the town of Malolos. From then on until March 29, 1899, when they were forced to evacuate to Gapan, Nueva Ecija, General Aguinaldo used the convent as the Palacio Presidential (presidential palace) of the first Philippine Republic. On March 31, 1899 (Good Friday), while Gen. Aguinaldo and his men were fleeing from the Americans, he ordered Gen. Antonio Luna to set the convent and the church (including its silver altar) on fire as part of their strategy called "scorched-earth policy," where everything will be rendered useless. The town was captured after a bloody fight.

The Church Rises Again. During the American occupation, the cathedral and the convent were rebuilt gradually from 1902 to 1936.

When Msgr. Pedro Abad became parish priest, the cathedral underwent a renovation. The windows were enlarged and lowered, arañas were installed and the patio was spruced up. Through the efforts of Ignacio Adriano, the baptistery was built under the supervision of Engr. Alfredo Aldaba and the late Cardinal Rufino Santos, blessed it on February 28, 1954. The pews were acquired through the efforts of Msgr. Marcelino Montemayor in 1957. The roof was replaced and a steel rafter was installed during the time of Msgr. Francisco Domingo (1955-61).

The Church becomes a Cathedral. The church underwent further renovations and repairs in preparation for its inauguration as the Diocesan Cathedral, and the installation of its first Bishop, Most Rev. Manuel del Rosario D.D. on March 11, 1962. In the advent of the reforms brought by Vatican II, the old altar was torn down and Msgr. Virgilio Soriano commissioned a new one in 1967. A statue of the Immaculate Conception donated by Amparo Bautista-Julian was also placed at the top of the bell tower. Stained glass windows, crafted by Krautt, were also installed in the upper part of the cathedral's facade: the Immaculate Conception patterned after Murillo's painting; the driving away of Adam and Eve from Paradise; and the Annunciation. The communion rail was also dismantled and the sanctuary was renovated when the cathedral was consecrated during the tenure of its second residential Bishop, Most Rev. Cirilo Almario, Jr. D.D. on December 4, 1976. Stained glass windows with the images of the Blessed Virgin of Lourdes and the Miraculous Medal were also place at the opposite windows in the sanctuary. Celing Marasigan, a religious painter from nearby Paombong, also improved the paintings of the four evangelist. The old convento which by this time was only half the size of the original, was reconstructed and expanded to accommodate the Bishop's residence, Chancery office and parish convent. This reconstruction of the historic Malolos convent was chaired by Dr. Johnny Reyes in preparation for the 400 years Christianization of Malolos.