1. 1735: The first recorded Moravian church service in Pennsylvania was held in Philadelphia on March 19, 1735. The Moravians were a Protestant denomination that originated in Bohemia and Moravia in the 15th century.

2. 1776: On March 19, 1776, the Pennsylvania Legislature approved the building of a state navy to support the American Revolution against British rule. The navy would go on to play an important role in the war, and several of its ships were built in Pennsylvania.

3. 1863: The state of Pennsylvania established a Board of Agriculture on March 19, 1863. The board was created to support the agricultural industry in Pennsylvania and to encourage farmers to improve their practices and increase their productivity.

4. 1909: On March 19, 1909, the Pennsylvania Railroad opened the world's largest railroad station in New York City. The station was called Pennsylvania Station and it served as a major transportation hub for the city until its demolition in 1963.

5. 1979: On March 19, 1979, a group of workers at the Three Mile Island nuclear power plant in Pennsylvania discovered that there had been a partial meltdown in one of the plant's reactors. The incident became one of the worst nuclear disasters in history and had a profound impact on the nuclear power industry.