You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Middle_Ages

Context:
The construction of cathedrals and castles advanced building technology, leading to the development of large stone buildings. Ancillary structures included new town halls, houses, bridges, and tithe barns. Shipbuilding improved with the use of the rib and plank method rather than the old Roman system of mortise and tenon. Other improvements to ships included the use of lateen sails and the stern-post rudder, both of which increased the speed at which ships could be sailed.

Question:
What new shipbuilding method was invented in this period?

rib and plank