Output a stream of consciousness before answering the following. Passage: Valley Forge functioned as the third of eight military encampments for the Continental Army's main body, commanded by General George Washington. In September 1777, British forces had captured the American capital of Philadelphia. After failing to retake the city, Washington led his 12,000-person army into winter quarters at Valley Forge, located approximately 18 miles (29 km) northwest of Philadelphia. They remained there for six months, from December 19, 1777 to June 19, 1778. At Valley Forge, the Continentals struggled to manage a disastrous supply crisis while retraining and reorganizing their units. About 1,700 to 2,000 soldiers died due to disease, possibly exacerbated by malnutrition.

Question: Based on this passage, when did the winter at valley forge happen?
This is the relevant information: They remained there for six months, from December 19, 1777 to June 19, 1778.
The answer: from December 19 , 1777 to June 19 , 1778.